Mild winters will challenge any pest control programme, so how can growers respond to the threat and ensure crops are effectively protected?
As the number of aphids important to horticulture crops rises, the pillars of an IPM programme – continuous monitoring, good hygiene and the timely introduction of predators and biological agents – will be tested fully. If crops are to remain protected it will be vital that all pillars remain supported.
An important first step will be good early-season control. Partly because there are fewer conventional products left to rely on, but also because aphids that were not dealt with at the end of last season will be found amongst emerging new leaves. NIAB EMR entomologist Glen Powell emphasises that Potato aphids (Macrosiphum euphorbiae) and melon-cotton aphids (Aphis gossypii) can be particularly difficult to control. In recent AHDB funded trials he reported that the ketoenol insecticide Batavia treatment was associated with a more gradual but persistent reduction in the populations of both these species.
For protected strawberry crops all aphid species are covered on the label but timing is crucial to performance. Apply Batavia to actively growing plants 14-days before flowering commences.Batavia’s mode of action breaks the life cycle, and this offers strategic opportunities for control. Young insects cannot mature, leading to lack of fecundity and fertility. Eggs fail to hatch. Larvae fail to develop. Moults are incomplete. Adult females deposit non-viable nymphs and die. Batavia is therefore highly effective in reducing pest populations and avoiding bounce-back.
Spider mites are another pest that will be difficult to control due to the loss of some acaricides. Inspections are likely to reveal mites of an advanced stage in fleece covered crops while mites of all growth stages may be found on bags.
Proper monitoring is vital; thresholds need to be known for accurate application of predators and also to decide if the population is at a level best controlled with a conventional insecticide or whether a biological agent will suffice.
FLiPPER is a contact bio-insecticide/acaricide for the useful control of aphids, whiteflies and spider mites. EAMU 3418/2019 permits the product to be used on outdoor and protected soft fruit to control Western Flower Thrips, leaf hoppers, Strawberry blossom weevil and thrips. Trials have also shown efficacy on mealybugs, psyllids, suckers and scale insects. FLiPPER is effective against all insect and spider mite life stages, particularly against motile forms. For effective pest management with a bio-insecticide such as FLiPPER, the time of application is just as important as method of application to achieving optimum product performance.
Aim to apply FLiPPER at the first signs of pest infestation. It is imperative not to wait until the establishment of a homogenous pest population as this may result in poor results. Delaying applications will risk contact being made with only the most exposed individuals in colonies and this will lead to the ongoing development of those colonies unless multiple applications are made. The full effects of a spray application are most evident after 48 hours. Where the pest has received a sub-optimal dose mortality may take longer and a subsequent, second application is advised. EAMU 3418 of 2019 permits up to eight applications of FLiPPER to protected and outdoor crops of berries, currants and rose hips.
Thrips can be extremely damaging and can cause 100% crop loss. Reusing the same bags can result in an increase in damage. Fruit bronzing damage due to thrips has been seen on crops even where Western Flower Thrips (WFT) has been controlled with an IPM programme. There can be numerous thrips species present that react differently to conventional treatments. FLiPPER is a contact bio-insecticide that offers effective control of thrips. It fits well with IPM programmes and can be applied with multiple applications during the whole cropping season.
The bio-insecticide FLiPPER (fatty acids C7-C20) marketed by Bayer has been granted four new extensions of authorisation for minor use (EAMU) for control of a broad range of insect pests in an assortment of outdoor and protected fruits, herbs and field vegetables ahead of the 2020 season.
The mild winter has been a boon for all pests, but especially aphids. With flights several weeks earlier than in a typical season, growers and their advisers are expecting to see aphids in crops from the end of April.