Courgette. Marrow, Squash and Pumpkin 2015
Contents
1. Red Tractor Assurance for Farms Fresh Produce Scheme Red Tractor Effective 1 September 2015 Red Tractor g Assurance for Farms Q Fresh Produce Scheme Welcome squash and pumpkin has been written to complement and avoid duplicating the generic principles of the Red Tractor Farm Assurance Fresh Produce Scheme standards It is advisable to read the Red Tractor Farm Assurance Fresh Produce standards before reading this crop specific module This module is designed to stimulate thought in the mind of the reader It contains crop specific guidance and standards where applicable in addition to the requirements stated in the generic Fresh Produce standards Ts crop specific module for courgette marrow Within this module the important requirements outlined in the crop specific standards section will be verified during the Red Tractor Farm Assurance assessment and compliance will form a part of the certification approval decision Disclaimer and trade mark acknowledgement Although every effort has been made to ensure accuracy Assured Food Standards does not accept any responsibility for errors and omissions Trade names are only used in this module where use of that specific product is essential All such products are annotated and all trademark rights are hereby acknowledged Notes Pesticide Information The Red Tractor Fresh Produce team has been working with Fera to provide tailored access to the LIAI2. The harvested fruit is often therefore well below size and taste specification Culturally there is little a grower can do to prevent the onset of the disease At present it is not possible to fully control the disease but regular field inspections can determine when the disease is first visible on the leaf and immediate fungicide treatment will certainly slow the rate of development of the disease on the plant Crops should be destroyed as soon as the grower has determined the last fruits have been harvested Fungicides for powdery mildew control In order to ensure that the cucurbit crop remains in production for as long as possible growers should make routine field inspections for early the signs of powdery mildew infection Usually by applying a suitable agrochemical at the first signs of the disease growers can slow the rate of development of the mildew This can achieve a potential two to three week extension to the life of the crop Unfortunately no matter how many times products are applied the powdery mildew will gradually infect the whole plant Growers should aim to contain the disease rather than continually apply fungicides in an effort to eradicate the disease Aprogramme of two to three well timed sprays alternating active ingredients where possible and starting when the infection is first seen normally just prior to fruit production is the most sensible agronomic approach There is a choice of products dep
3. of time to maturity in the UK Many of these storage squashes are planted drilled to produce fruit in a very short non cyclical UK season Cucurbits are very sensitive to frost They can be planted under protection as early as the first week of April or direct drilled as late as the second week in July They may be planted without protection from mid May Drilling planting times depend on the cucurbit type being grown the marketing of the crop and the value of the fruit Plant spacings are dependent upon cultural techniques and harvesting techniques and the type of crop being grown Growers should decide upon the correct plant spacings to suit their own production Standard plantings of summer squashes require approximately 10 000 plants per hectare Non storage cucurbits are usually planted as early as possible in the season and then sown planted in succession sequentially into July or early August Early plantings may be forced by producing plants with heat under glass and planted into early seedbeds prepared with polythene mulches to promote soil temperatures and suppress weeds and covering with low polythene tunnels cloches to ensure frost protection and to elevate temperatures in early spring As successive crops are planted drilled and the probability of frost diminishes so these high inputs also diminish culminating with crops being direct drilled into stale seedbeds without protection Whilst storage cucur
4. usually dictated by market forces but the means of handling of the product is determined by the softness of the skin viz Courgettes need more careful handling than pumpkins Fruit debris which is left in the field following a harvesting run is a prime source of virus and disease so growers should implement systems where discarded fruits and plant material are removed from the field after each harvesting session Proper harvesting hygiene is also essential to limit the build up of other diseases and pests such as whitefly Harvesting techniques should follow strict hygiene procedures which ultimately cut down on plant and harvested fruit contamination RESIDUES AND CONTAMINANTS Red Tractor Farm Assurance Fresh Produce is aware that a key area in the production of fresh produce which requires continued attention by growers and their advisers is that of keeping pesticide residues to a minimum The issue is not just one of meeting the MRL trading standard but ensuring that any individual or multi residues are kept as low as possible below this level The key targets are Optimising late application of fungicides and insecticides to the edible part of the crop Optimising the use of post harvest treatments E Ensuring minimum harvest intervals are followed E Ensuring that application equipment products correctly is applying APPENDIX 1 TYPICAL APPLICATION RATES FOR NUTRIENTS Currently there are no residue issues with this
5. virus infection from previous cropping The alternative hosts for these viruses are other cucurbits crop trash and most importantly indigenous UK weeds Fields which have had a history of the virus especially if they are adjacent to non cropped areas that support an unchecked growth of wild flowers and weeds are especially likely to be susceptible areas for the viruses Late crops planted near to early crops already showing symptoms of the virus are also at very high risk The best method of reducing the risk is to plant drill crops away from known virus risk areas Growers unlucky enough to lose the majority of the crop to virus and where roguing is not a viable option should consider any future cropping carefully The infected plant material left in the field represents a major reservoir of virus particles which is likely to influence future cucurbit cropping on the farm Growers should consider treating the crop with a non selective herbicide to completely desiccate the crop thus limiting virus carry over on crop debris Courgette and marrow crops which are mildly infected with virus at the start of the harvesting season are prone to rapid virus spread if the fruits are cut from the plant An infected plant will pass virus particles onto the knife which are transferred when the knife is used to cut fruit from the next plant Some growers regularly disinfect their knives between cuts which helps but the only sure way to preve
6. 3 885739 Email agriculturefansf org Web www nsf foodeurope com SFQC SFQC Ltd Royal Highland Centre 10th Avenue Ingliston Edinburgh EH28 8NF Tel 0131 335 6605 Email redtractorfasfqc co uk Web www sfqc co uk e kiwa p Partner for progress Kiwa PAI The Inspire Hornbeam Square West Harrogate North Yorkshire HG2 8PA Tel 01423 878878 Email paienquiriesfakiwa co uk Web www kiwa co uk pai FJ NIFCC Northern Ireland Lissue House 31 Ballinderry Rd Lisburn Northern Ireland BT28 2SL Tel 028 9263 3017 Email infofanifcc co uk Web www nifcc co uk FY SAI GLOBAL ASSURANCE SERVICES SAI Global Assurance Services Ltd PO Box 6236 Milton Keynes MK1 9ES Tel 01908 249973 Email agrifoodfasaiglobal com Web www saiglobal com assurance 4 QWFC Wales PO Box 8 Gorseland North Road Aberystwyth SY23 2WB Tel 01970 636688 Email infofawlbp co uk Web www wlbp co uk T 01932 589 800 E producefdaredtractor org uk www redtractorassurance org uk
7. 8 Maintain crop hygiene during the harvesting period 19 Ensure prompt crop removal after the last fruits have been removed Desiccate crops infected with gummosis scab and virus in order to prevent carryover in crop trash Plant protection product choice APPROVED USES NOT INCLUDED ON THE PRODUCT LABEL In many circumstances particularly for minor crops product labels do not include all of the approved uses and growers wishing to check the approval notice of a particular product should note that this information is available using the LIAISON search accessible via their RED TRACTOR Farm Assurance home page after logging in A search on the Extension of Authorisation page of LIAISON by crop or product name should yield a results page A click on the product name should link to a summary of the approval information Near the bottom of the summary is the specific extension of authorisation number e g 0246 09 and this link will open up a pdf of the current document giving details of the extension of use PEST DISEASE AND WEED CONTROL Pest control Agronomically established plants are treated slightly differently depending on the method of production Plants covered with low tunnels cloches need to be protected from wind frost and general cold conditions for as long as those conditions persist These covers can be temporarily removed drawn back during favourable conditions and replaced if conditions deter
8. SON database for all Red Tractor Fresh Produce members This system allows individual growers access to all information for plant protection products approved for use under the Red Tractor Fresh Produce Scheme LIAISON can be accessed under the Produce tab via the Checkers and Services page where you will also find a user manual Searches will be filtered specifically for the crops for which you are registered Once you have logged onto the site and clicked on the LIAISON hyperlink you will be directed to the LIAISON home screen You will need a username and password and these will be sent once you have registered http assurance redtractor org uk rtassurance services Registration members eb General Introduction Following a systematic approach will help growers identify and manage the risks involved in crop production This module is based on a typical crop production process and food safety health amp safety environmental and quality hazards are identified Appropriate controls may then be established to minimise risk Food safety and health amp safety issues always take precedent over quality and environmental controls The layout of this module follows the same structure as that used in the Red Tractor Farm Assurance Fresh Produce Standards The content of the module is reviewed prior to the issue of updated editions The review process considers both new developments and all relevant technology which has emerged sinc
9. bits can be produced in the same way it is more usual for plants to be raised for transplanting or direct drilled once the risk from of frost and other adverse weather conditions has passed Propagating in modules or blocks is very straightforward Module size and type is usually decided between the grower and the propagator and is normally linked to the planting technique Seeds are usually hand sown taking 2 4 to 3 weeks from seeding to seedling maturity The seedlings are usually fed 2 weeks after sowing and hardened off after 18 days Agrochemical treatment of developing plants is rarely necessary The use of biodegradable polythene mulches in cucurbit production is increasing growers should make every effort to re cycle any non biodegradable plastic if this is not possible then it should be sent to a registered landifill site Growers must not burn plastic waste see DEFRA s Code of Practice for Protection of Air The cucurbit harvest season in the UK is approximately from the second week in June to the end of October Most of non storage cucurbits are harvested by the first week of October Pollination The production of fruit on cucurbit plants is dependent on pollination but some plants such as courgettes can produce their fruit parthenogenetically Fruit produced in this way is usually smaller less abundant and will not contain viable seeds Growers who wish to achieve full potential yields should actively enco
10. crop for currently approved pesticides Care should be taken when selecting sites to avoid areas where there has been historic use of dieldrin This is due to the ability of cucurbit crops to extract this highly persistent pesticide from the soil particularly during drier seasons Major nutrient requirements kg ha Soil Index 0 1 Nitrogen N 100 Phosphate P O 125 100M 2 Notes The recommendations assume overall application A starter fertiliser containing nitrogen and phosphate may be beneficial A small amount of nitrogen may be needed if SMN levels are low in the 0 30cm of soil Apply no more than 100 kg a N in the seedbed Apply the remainder as a top dressing when the crop is fully established M Maintenance dressing Do not forget to deduct nutrients applied as organic manures NOTES Red Tractor Assurance for Farms Crop specific Module Courgette Marrow Squash and Pumpkin Assured Food Standards 2015 ee NOTES a Red Tractor Assurance for Farms Crop specific Module Courgette Marrow Squash and Pumpkin Assured Food Standards 2015 Certification Body Beef and Lamb Certification NSF Certification Hanborough Business Park Long Hanborough Oxford 0X29 8SJ Tel 0199
11. d as potential virus transmitters and should be treated Therefore growers are encouraged to carry out regular field inspections to determine the level of aphid incidence Whenever virus infected plants are seen growers should remove all the plant from the field and destroy completely by burning There are a limited number of foliar applied insecticides approved for cucurbits Those natural predators which help reduce aphid numbers include hover flies ladybirds lacewings and parasitic wasps The incidence of these predators should be determined prior to choosing the most suitable method of aphid control Foliar applied aphicides If aphids are found at any stage in the development of the crop growers have to make an objective choice to control them This action is very important in areas prone to CMV or ZYMV if transmission of these viruses is to be limited There is a limited range of aphicides approved for use in cucurbit crops Early aphid attack can be the most likely to cause premature crop death through early virus transmission Wherever field inspections show good predator activity in marrows and courgettes and certainly where bees are active in the crop growers should elect to use products containing pirimicarb as both predators and pollinators are relatively unaffected by this active ingredient In heavy infestations where the predator pest ratio is greatly in favour of the pest growers may wish to reduce the bala
12. d by woodlands or extensive non managed areas of vegetation Geographical location Cucurbit crops can be grown over the whole of the United Kingdom and can be direct drilled or planted as modules and blocks Endemic weed spectrum This is a critical aspect in choosing the correct land for cropping because herbicide choice is extremely limited Soil type and tilth The crops can be grown over a range of soil types Heavier moisture retentive soils are suitable for the planted crop but can impair emergence of the early drilled crop Soils containing a proportion of stones may be suitable for crop establishment but Class 1 fruit production may be impossible due to physical damage as the crop trails Soils where only a poorer tilth is achievable still have the potential to establish a good crop provided growers have the facility to raise plants in blocks or modules first Rotation It is not advisable to follow a cucurbit crop with another cucurbit Growers should aim to plan for at least a three year rotation in order to limit soil borne disease infection from one cucurbit crop to the other Cucurbits that follow tuber crops such as potatoes are likely to be severely at risk from the competition from volunteers from the tuber crop ENVIRONMENTAL PROTECTION amp CONTAMINATION CONTROL THE BASIC APPROACH TO CROP PROTECTION Integrated crop management 1 Pick the crop type required by the market 2 Select the correct fie
13. ds to reduce the risk of damage from these pests Early cultural weed control can help to reduce the risk of both cutworm Agrotis spp and bean seed fly Delia platura Regular field monitoring should be undertaken to determine pest activity Even though covers may completely protect the crop from attack the adult stages of both pests can lay their eggs prior to cultivation and thus growers should inspect both protected and unprotected crops The damage from bean seed fly is sporadic and localised The most serious damage to cucurbits occurs on plants raised in peat blocks soon after planting out Plants will collapse completely often within seven days of planting out As the flies prefer to lay their eggs on freshly disturbed soil planting or drilling into a stale seedbed without the need for early hoeing may reduce the likelihood of attack Cutworm control can be achieved culturally through suppression by heavy irrigation or periods of heavy rain Aphids The main insect pests of the developing crop are aphids the main species are the peach potato aphid Myzus persicae and the melon amp cotton aphid Aphis gossypii Whilst heavy aphid infestation can stunt the plant and delay maturity their main role is as a vector for cucurbit viruses Any aphid infestations certainly at all stages of the crop up until first production and in virus prone areas well into the production cycle and fruit development stage should be viewe
14. e recommendation of nutrition should wherever possible be taken from a FACTS certificated advisor Nutrients can be applied in several ways Whilst the majority of the nutrients can be applied to the seedbed it is usual to apply a top dressing to the crop either as a prilled or pelleted product a series of foliar nutritional sprays or as a liquid nutrient feed through the drip lines fertigation If growers elect to use granular fertilizers as a top dressing care should be taken to avoid pellets prills lodging in the leaves and growing points which could lead to scorch and the subsequent development of disease on the damaged tissue Microelements such as boron zinc manganese and iron are all important for the successful growth of the crop These elements should be applied according to analysis results or to correct deficiencies visible as leaf symptoms Cucurbits will not tolerate an incorrect pH Growers should react to soil analyses and target for a pH of 6 5 Growers may elect to apply the majority of nutrients as organic manure prior to drilling or planting Care should be taken in dry conditions as this may lead to an increase in the risk of crop damage IRRIGATION Crops grown on grade one moisture retentive soils can produce high yields of excellent quality fruit through the season Most crops however will require supplementary irrigation to achieve Class 1 yields HARVEST AND STORAGE The timing of harvest is
15. e the last review was completed and which have been found to be both workable by the grower and beneficial to the environment The aim is to transfer such information and technologies to growers Acknowledgements Red Tractor Farm Assurance Fresh Produce gratefully acknowledges the contribution of all consultees in the preparation of this protocol particularly Neil Cairns of Barfoots Red Tractor Assurance for Farms Crop specific Module Courgette Marrow Squash and Pumpkin ADDITIONAL REQUIREMENTS AGAINST CURRENT STANDARDS CROP SPECIFIC STANDARDS CHOICE OF VARIETY OR ROOTSTOCK AND PLANT HEALTH CERTIFICATION SITE AND SOIL MANAGEMENT ENVIRONMENTAL PROTECTION AND CONTAMINATION CONTROL PEST DISEASE AND WEED CONTROL NUTRITION IRRIGATION HARVEST AND STORAGE RESIDUES AND CONTAMINANTS APPENDIX 1 TYPICAL APPLICATION RATES FOR NUTRIENTS ADDITIONAL REQUIREMENTS AGAINST CURRENT STANDARDS None for this crop module CROP SPECIFIC STANDARDS None for this crop module 02 02 03 03 05 06 10 10 10 10 11 Assured Food Standards 2015 Ea GUIDANCE CHOICE OF VARIETY OR ROOTSTOCK AND PLANT HEALTH CERTIFICATION BACKGROUND This protocol covers the field production of marrows courgettes squashes and pumpkins Although it is technically possible neither melons nor cucumbers are usually grown commercially in UK outdoor situations To understand where each product fits into the overall family
16. ending on the crop Courgette growers can use products containing either azoxystrobin bupirimate or mepanipyrim Marrow growers can use products containing either bupirimate or fenarimol Squash and pumpkin growers are able to apply products containing fenarimol There are now varieties of courgette on the market which show significant tolerance to powdery mildew A commodity substance approval for potassium bicarbonate for the control of powdery mildew is also available Commodity substances are chemicals which have a variety of non pesticidal uses and also have minor uses as pesticides Food grade potassium bicarbonate can be used to give effective control of powdery mildew Virus diseases The main virus in the United Kingdom is cucumber mosaic virus CMV Since the end of the 1980 s the potentially more troublesome zucchini yellow mosaic virus ZYMV has become more prevalent in the UK Both viruses are devastating to the plant and have the potential to firstly reduce yield secondly to distort and drastically reduce marketability of the fruit and finally may even cause premature plant death Sequentially cropped non storage crops are primarily affected by yield loss and reduced marketability Infected storage squashes simply do not yield or if they do the fruit is so poorly formed that it is not marketable so aphid vectors should be prevented from transmitting the virus To some extent growers can determine the potential for
17. es the grower the best opportunity to establish a crop iv growers can elect to use residual herbicides which give limited control of some emerging weed seedlings These herbicides should be used prior to weed emergence As is usual with residual herbicides there should be sufficient moisture in the seedbed for the herbicide to work efficiently v cultural control can be achieved mechanically by using tractor mounted or steerage hoes Growers who elect to use these implements should plan their planting spacings to accommodate them Care should be taken to avoid excessive root pruning that can cause plant death Growers may also elect to use brush weeders which again requires the correct set of plants in the field vi as the plants increase in size and if weeds are still a problem especially those in close proximity to the plants growers can elect to hand hoe the crops Pickers also usually remove weeds in non storage cucurbits as they harvest the first flush of fruits Weeds which have not been controlled in the crop and which through their growing pattern and natural size have grown taller than the crop may be killed with a mechanical or hand held weedwipers using a suitable non selective herbicide Suitable weedwiper models should be chosen in order to avoid the herbicide dripping on to the crop Non selective pre cropping herbicides The choice is dependent on the developing weeds Flushes of annual weeds can be control
18. iorate When conditions become consistently favourable the tunnels are removed but the plants are then more readily susceptible to attack by parasites and virus vectors Growers who covered their crop with floating mulch usually choose to keep their crop covered until flowering However the choice of mulch can be critical agronomically Non woven fleece covers can if they remain intact provide a complete barrier against any insect parasites that may infest the aerial parts of the crop obviating the need to apply an insecticide for the control of these pests Plastic mulches have to be perforated so although they have the potential to produce more heat units for the growing crop they allow access to insect parasites and therefore cannot be relied on as part of an integrated control of pests The removal of tunnels and floating mulches is at the discretion of the grower Factors such as heat moisture weed levels insect numbers wind damage and the chance of frost should all be taken into account prior to removal At the latest crop covers should be removed by the time the flower opens to facilitate pollination Insect pests can be categorised into those which attack and kill the plant and those which parasitise the plant stunting its growth and more importantly spreading virus Cutworm and bean seed fly As there are now no approved insecticides for either of these pests it is essential to employ cultural control metho
19. lds using the following criteria aspect soil type previous cropping soil condition protection irrigation potential weed spectrum 3 Try to avoid drilling or planting in close proximity to wild flower and weed areas that may act as a reservoir for virus Consider the physical separation of cucurbit plantings drillings in order to limit disease spread between sequential crops 4 Wherever possible prepare seedbeds in advance to creating the opportunity to burn off weeds prior to planting or drilling to produce a stale seedbed Apply a proportion Where agronomically practical if it is feasible to safely apply nutrition after crop emergence or all of the nutrition in the seedbed Take the advice of a FACTS qualified advisor On lands prone to slugs set traps to evaluate slug populations If populations are high aim to find another site Failing this apply baits in advance of drilling to minimise crop damage and financially acceptable choose physical barrier methods to suppress weeds and prevent aphid attacks on the developing crop Evaluate the need for residual herbicides whilst bearing in mind the potential growth check to the crop due to phyto toxic effect of herbicides Evaluate the advantages in planting the crop rather than drilling Consider the recycling of polythene mulches and low tunnels Field inspections should be carried out to determine cutworm activity Do not treat prophylac
20. led through the application of contact herbicides containing diquat or products containing glufosinate ammonium Weed flushes consisting of both annual and perennial weeds can be treated with systemic herbicides containing glyphosate Residual soil acting herbicides An extension of authorisation for isoxaben is available to growers of the direct drilled and just planted crop Isoxaben is a residual chemical that controls a range of weeds in the average spectrum of weeds common to UK farms In line with most residual herbicides its activity is severely reduced in dry soil conditions and it only has activity on weeds that have yet to emerge Growers with knowledge of their weed spectrum should check against the activity spectrum of the herbicide prior to considering its use as part of their weed control programme Growers can also elect to use the extension of authorisation use for propyzamide NUTRITION The application of nutrients should be approached preplanting Nutrient application should be made in accordance with soil analysis results In practice even though mineral nitrogen can be assayed the test is currently disproportionately expensive and the results difficult to link to objective nutritional recommendations Clearly as more research is carried out correlation between mineral nitrogen testing and nitrogen fertiliser recommendation will become more straightforward Advice on the interpretation of analysis and th
21. mmosis Cladosporium cucumerinum and powdery mildew Erysiphe cichoracearum and Sphaerotheca fuliginea Both of these diseases are linked to weather conditions and can for the most part be predicted Gummosis Gummosis or Scab is a disease that develops rapidly in warm 17 21 C wet weather conditions and cool nights accelerate the symptoms It spreads primarily from infected material and subsequently through wind blow and rain splash The disease has the potential to destroy all marketable yield within a very short space of time Courgette crops are particularly vulnerable to the disease that first appears as a vague leaf symptom and then manifests itself on the developing fruits The fruits firstly develop dark green spots on the surface which then sink into the flesh and begin to weep a gummy substance All infected fruit is unmarketable Whilst courgette crops can suffer from this disease it is often particularly noticeable in late season marrow crops and also pumpkin crops With both crops the scab often dries out and appears to heal however in marrow crops this is still unmarketable and with storage squashes and pumpkins this scab can then breakdown to produce rot spots An integrated disease prevention approach is the best approach for growers Previous cropping has to be taken into account with at least a three year rotation between crops Crops exhibiting signs of infection should be identified as soo
22. n as possible and the positioning of later drillings should wherever possible be re evaluated Care should be taken to avoid the unnecessary transference of crop material to other cucurbit sites Waste fruit should be destroyed or dumped in areas well away from production sites Infected crops should be desiccated in the field prior to cultivation to remove debris on which the disease can survive Fungicides for gummosis control Currently there are Powdery mildew Although gummosis has the potential to be a most devastating disease of courgettes it is powdery mildew that invariably kills the cucurbit plant This disease overwinters on weeds and its spores are carried long distances in the air Normal UK summer temperatures and humidity favour the development of the disease The disease will not however develop well in prolonged periods of heavy rain where the leaves remain continually wet The disease quickly spreads over the surface of the leaves acting primarily as a carbohydrate sink diverting the photosynthates away from the developing fruits Once the leaf is covered it dies and the plant begins to defoliate Once the disease is well established the older leaves are lost faster than new ones are produced so fruit development quickly ceases In the case of storage squashes fruits are set prematurely before the required size specification is met and often before the sugar levels have reached their desired potential
23. n lies with the grower Prevention of pest damage starts at this point as the early cultural control of weeds prevents any chance of re seeding Cutworms Agrotis spp the caterpillars of several species of noctuid moths are more likely to be a problem in fields where large sized weed cover precedes last minute ground preparation Cutworms graze at the base of the plant severing the stem and the killing the plant Prolonged weed cover remaining uncultivated until immediately prior to planting or seeding can also increase the risk of bean seed fly Delia platura attack Attacked plants are usually unable to recover and quickly die Slug monitoring should be carried out prior to drilling the crop Slugs Derocerus and Milax spp are not usually a problem in the cucurbit crop However in fields where slugs are an historical problem or where growers have no historical data covered slug monitoring traps set prior to the drilling of the crop can indicate whether control measures are warranted prior to seeding or whether an alternative field would be more suitable DRILLING AND TRANSPLANTING Drilling and planting dates Drilling and planting is generally determined by product group and the storage potential of the fruit produced Courgettes and marrows are usually produced from sequential drillings and plantings through the season The drilling and planting of storage squashes is usually determined by their growing cycles and length
24. nce by an instant knockdown of aphids Here courgette and marrow growers have the option of using Thiacloprid based products Growers also have the option of treating aphid infestations with fatty acid based products that have a zero harvest interval Molluscs Slug monitoring is an important part of slug control Baits applied to a small area and then covered to prevent vertebrate animals eating any of the dead slugs provide a good way of monitoring activity prior to drilling the crop Depending on the numbers of slugs trapped growers can take decisions ranging from no action applying pellets prior to drilling especially important in the mulched crop or even choosing another site The choice of active ingredient for the control of slugs in cucurbits is now limited to Metaldehyde but there are a wide choice of products containing this active ingredient Growers should elect to use those products that are formulated to provide good longevity Control is usually only warranted at the seedling stage Other pests Another pest of cucurbits is two spotted spider mite Tetranychus urticae This pest is only seen occasionally but can be very destructive in hot dry conditions Mites can be treated in all cucurbits biologically Encouraging ladybird larvae and lacewings into crops will have a beneficial effect on mite control Other insect pests include whitefly family Aleyrodidae and thrips family Thripidae Field scale producti
25. nt this type of virus transmission is to twist the fruit from the plant and only then trim the stalk end The knife does not therefore touch the mother plant There are now virus resistant varieties of courgettes and marrows on the market which should be evaluated by the grower as part of an ICM approach Other diseases Minor diseases such as downy mildew Pseudoperonospera cubensis and Sclerotinia stem rot Sclerotinia sclerotiorum are sometimes seen in the crop but agrochemical treatment is rarely appropriate WEED CONTROL Weeds not only compete with the crop they also carry diseases and viruses which can subsequently infect the crop Growers should identify the fields weed flora and plantings drillings should be made with regard to weed incidence and diversity Weed control should be planned in the previous season There are six main strategies i avoid those fields where weeds are very prevalent ii on very early plantings and drillings having made up the seedbed install the method of irrigation usually trickle or drip lay a black polythene mulch which suppresses weed growth and then plant through the polythene being careful not to cut it anymore than necessary establish a stale seedbed by destroying weed flushes as many times as possible prior to the drilling planting emergence of the crop If a grower has no choice other than to choose soils with a large weed seed reservoir then transplanting the crop giv
26. of Cucurbitaceae it is important to look botanically at each product and from where its name was derived Marrow is the English word for the Italian zucca and the French courge The English language has taken the French word courge combined it grammatically with the French for small or diminutive ette to produce Courgette meaning small marrow The American language has taken the Italian derivative to produce zucchini which is now the American word for courgette and the Italian for marrow Courgettes are therefore classed as small marrows Squash is the American Indian term covering most summer fresh and winter stored cucurbits Summer cucurbits may be broken down into marrows and courgettes Gem squashes also fit into this category Winter squashes are essentially storage squashes grown to full maturity usually picked after the skin has set when the plant is usually senescing or has already senesced A pumpkin is a winter storage squash If cooked correctly the skins of pumpkins and all squashes can be edible Botanically summer squashes are varieties of Cucurbita pepo Winter squashes may be Cucurbita moschata C maxima or C pepo Pumpkins are either C pepo or C mixta The whole group may be classified into two main types Summer cucurbits are broken down into non storage squashes such as marrows and courgettes Gem squash can also fit into this category Winter squashes are essentiall
27. on is rarely affected by the occurrence of these pests and thus treatment is rarely warranted but pumpkins can be plagued by whitefly which can be treated with fatty acid based products Pollen beetles occasionally infest the open flowers but do not appear to affect the plant or its production Their presence can dissuade bees from the flowers which can have a negative effect on pollination and hence shape on certain squash types Biological control organisms Growers can elect to control spider mites by biological means Growers of all cucurbits have the option to introduce the predatory mite Phytoseiulus persimilis Field trials have shown good control of spider mites is achievable with Phytoseiulus If regular field inspections give an early indication of a build up growers should contact distributors of this predator and discuss with their technical representatives the feasibility of biological control in this circumstance If whitefly builds to excessive levels in pumpkins growers have the opportunity to apply fatty acids to reduce pest levels These products are less damaging to beneficial predatory and non target insects DISEASE CONTROL As the plant develops from seedling stage through its vegetative stages it is rarely visibly plagued by disease The symptoms of diseases generally become visible on the plant when it changes its growth habit from vegetative to reproductive There are two main diseases of cucurbits gu
28. tically In un barriered crops inspect plants regularly for aphid infestations and treat accordingly Remove mechanically or by hand any remaining troublesome weeds Field inspections are carried out for virus disease identification and any plants exhibiting symptoms of virus disease are rogued out and burned where necessary Evaluate the bee activity in the crop If necessary bring in hives to supplement wild bee activity As the crop changes from vegetative to reproductive growth and sometimes before in some very susceptible areas use weather patterns to predict potential disease development times Use these predictions in addition to regular field inspections to evaluate timings for main disease control Continue to make field inspections throughout the life of the crop A critical time for aphid infestation and thus virus infection is when courgette crops are being harvested Assess aphid numbers and the numbers of actively feeding predators then choose the most suitable form of control Aim to preserve predators if your inspection indicates a satisfactory predator prey ratio Treatment with a non predator friendly insecticide should be made only when bees are not foraging in the crop i e late evening 17 Viruses are transmitted in frequently harvested crops on harvesting knives Twist the fruits from the plant and trim the stalks prior to packing rather than cut straight from the plant 1
29. urage pollinators into the crop Bees are the best of all potential pollinators and UK field grown cucurbits are usually fully pollinated by wild bees Very high and low temperatures can also affect pollen viability resulting in poor pollination If too much nitrogen is used resulting in excessive vegetative growth or plants were improperly spaced bees may have difficulty locating the flowers Growers who expect to experience pollination problems can elect to bring honeybee hives into the crop to increase the level of pollination Growers can also elect to sow suitable wild flower mixtures around the boundaries of fields and within wheelings to encourage wild bees into the vicinity of the crop Growers should never apply agrochemicals at times when bees are actively foraging in the crop even if the label does not state Harmful to Bees Growers should always discuss the timings and use of agrochemicals with beekeepers prior to application Site history Product type geographical position site selection and aspect previous cropping weed spectrum soil type and tilth and irrigation potential all play a critical part in the production of the crop Compromising on any one of these points will almost certainly lead to unnecessary crop inputs and thus compromise the principles of ICM One should also be mindful of historical virus issues where cucurbits have been previously grown with particular emphasis on fields which are bordere
30. y storage squashes These squashes are grown to full maturity picked when the skin is set and when the plant is usually senescing or has already senesced The storage squashes may be sub divided into short term storage where the skins are semi set and long term squashes winter squashes where the skins are hard set SITE AND SOIL MANAGEMENT SITE SELECTION Site selection depends greatly on market forces and the harvest timing of the crop Early crops should be produced on south facing slopes free of frost and with good wind protection Cold exposed sites are generally unsuitable for the production of the crop Sites prone to flooding high winds and frost should be specifically avoided SITE MANAGEMENT Soil management Ground preparation and early pest prevention Ground preparation should wherever possible follow an overwintered frost conditioned fallow Whilst not always practical in very early planted crops the early preparation of land not prone to slumping can lead to a heavy flush of weeds just prior to drilling and a well timed non selective herbicide will control the majority of these emerging weed seedlings This is a key husbandry technique approach in view of the extremely limited range of approved selective herbicides If the crop is to be direct drilled soils which tend to slump are not generally suitable for this stale seedbed approach The choice of equipment for ground preparatio
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