Controlling codling moth in apple and pear

Controlling codling moth in apple and pear

Why control codling moth?
Codling moth (Cydia pomonella) is one of the most important insect pests of commercial apple and pear growing in the UK. The caterpillar larvae burrow into the fruit giving the pest one of its common names apple maggot. Direct damage to the apple or pear fruit from either a tunnel within the fruit or a sting on its skin makes table fruit unmarketable. Codling moth larvae feeding on the fruit core results in early fruit drop affecting the yield of crop destined for processing. In addition secondary disease infection of wounds can risk tainting products from processed apples.

How to control codling moth?
There are a number of products available for the management of codling moth (C. pomonella) in the UK. The suitability of each of these will depend on the cropping system being used, pest pressure and other components within a sites Integrated Pest Management (IPM) programme. One of the biggest challenges with controlling codling moth is application timing. There is only a limited window when the pest is outside of the fruit where it is most susceptible. Ovicides targeting eggs have only the 7-10 day window it takes the eggs to hatch. Larvicides then have a limited period to make contact with the codling moth larvae as they move from the egg to the point at which they enter the fruit (Vagabundierphase). Timing therefore, of any insecticide used against codling moth, is very important to allow a product to provide optimal performance.

How to improve timing of insecticide applications?
In order to maximise the performance and cost efficiency of insecticide applications it is important to ensure optimal application timing. Correct timing of pesticide application can be determined by a combination of computer environmental modelling, monitoring traps, site history and crop walking. Information from all of these pest forecasting tools are sued by apple and pear growers to determine when an action threshold is reached; the point at which the risk from the pest has reached a point where intervention is required to prevent the pest insect exceeding an economic damage threshold. Pheromone monitoring traps should be used from petal fall until harvest and checked weekly. The action threshold of trapped adult moths will vary depending on location, cropping system and time of year.

Codling moth control strategies
When an action threshold is reached, there are a range of control options available for UK apple and pear growers. These range from older chemical pesticides (spinosad), relatively recently registered synthetic chemistry (chlorantraniliprole) or biological control options such as mating disruption (pheromones) and biological insecticides such as granulovirusMore information on currently approved insecticides can be found on the Health and Safety Executive website here.

Application strategies for Madex Top
With typically 1.5 generations of codling moth (Cydia pomonella) per year in the UK, there are a number of application windows for insecticide treatments. Increasingly, with milder winters and and hotter summers, there are 2 generations per year in especially I southern England. The most important risk periods being targeting the first generation around egg hatch in June and then again eggs hatching from the second generation closer to harvest in August to September. Insect monitoring is key to accurately identify when these periods occur as their timing and severity can be affected environmental conditions starting the in the previous autumn.

Targeting the first generation is key to season long pest management as at the end of the first generation pupae can either emerge as the second generation or overwinter to form the first generation the following year. Whilst Madex Top can be used to control codling moth (Cydia pomonella) by itself, it is common practice to use alongside synthetic chemistry in an integrated pest management approach. Optimal application timing for Madex Top is typically 1-2 weeks before a synthetic chemical insecticide would be applied, with the Madex Top virus timing aiming to target the codling moth population at the start of egg hatch rather than peak egg hatch. This different optimal timing window also allows the chemistry to be saved and used during periods of higher pressure.

Combining Madex Top with a synthetic chemical insecticide and rotating the active ingredient the pest is exposed to is also good agricultural practice to help manage the potential risk of development of resistance which would increase if the pest was consistently only exposed to one mode of action. Baculoviruses, such as GpGV in Madex Top, have a very different mode of action to synthetic chemistry and are an excellent resistance management tool.

Benefits to the environment
The narrow spectrum of activity of Madex Top against only the target pest species (codling moth, C. pomonella) causes minimal effect on pollinators or non-target beneficial organisms so not disrupting any effect the naturally present beneficial predators are having on other potential pests within the apple or pear orchard ecosystem.

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