Introduction to British pear growing

Introduction to British pear growing

Approximately 1,500 ha of pears for fresh consumption are grown in the UK. Of this, around 90% of the crop harvested is sold on the domestic market. As has been seen in many horticultural crops the last 50 years has seen significant intensification in crop management, from more efficient spacing and canopy management helping to increase ease of harvesting along with increased use of pest management inputs. There are however challenges with managing pests in these more intensive systems. Codling moth (Cydia pomonella) is a significant pest of pears. The use of chemical insecticides to control codling moth can however inadvertently disrupt the natural ecosystem resulting in increased problems by another insect species.


Codling moth in pear

Codling moth (Cydia pomonella) is a significant insect pest of pear, with larvae of this lepidoptera burrowing into the fruit ruining it. More often thought of as a key pest in apple, because of the larger cropping area, management of codling moth in pear has an extra dimension of complexity. Applications of broad acting chemical insecticides also kill natural predatory insects found within the pear orchard. These natural populations of predators are responsible for the suppression of other insects which otherwise would increase in numbers sufficiently to also become a pest of pear crops. An example of this are Anthocorid bugs (such as Anthocoris nemoralis) which are natural predators of pear psyllids (Cacopsylla pyricola and C. pyri).


Psyllid pest insects in pear

Pear psyllid (Cacopsylla pyricola and C. pyri, Psyllidae) can be an important pest of pear in the UK. Adults overwinter on or near the pear orchard returning to the trees in early spring to reproduce. Pear sucker mostly feed on pear tree leaves which, whilst it may cause necrotic areas to appear on the leaves, does not cause economic losses when at low levels. Psyllid feeding on young fruitlets early in the season can result in the tree aborting them and dropping them and late season feeding on near to harvest fruit causes skin blemishes. The main economic impact of the pest however is the honeydew they produce whilst feeding supporting the growth of sooty moulds on the fruit. Natural populations of Anthocoris nemoralis and A. nemorum predatory bugs are able to manage the populations of pear psyllid (C. pyricola and C. pyri) preventing them from increasing to a level where they cause significant crop damage. However, applications of broad acting chemical insecticides, especially from post-blossom onwards reduce the Anthocoris spp. populations. Following a chemical insecticide application, populations of pear psyllid are able to recover faster and become a pest due to fewer Anthocorids present to control them.

In addition to Anthocoris spp. there are a number of other polyphagous natural enemy predators such as chrysopids, coccinellids, syrphids and spiders which feed on insects which would otherwise cause crop damage in top fruit orchards. The use of Madex Top as a very specific acting codling moth control product, controls the pest whilst not affecting any of these important non-target organisms.


Helping to manage Psyllids in pear

Baculoviruses such as the CpGV (Cydia pomonella granulovirus) in Madex Top are very specific in the insects they are able to kill. Madex Top is only able to infect and kill codling moth (C. pomonella). Therefore, application of this natural biological pesticide will control the pest codling moth whilst having no negative effect on Anthocoris spp. allowing them to continue to supress populations of pear psyllid.


Madex Top to control codling moth in pear

In the UK, depending on location and weather codling moth have 1 to 2 generations per year on pome fruit (apple and pear). Madex Top (LINK) is an approved biological insecticide for the control of codling moth (Cydia pomonella) in apple and pear. The virus particles within Madex Top have to be ingested by the codling moth caterpillar and therefore application timing is key to successful use of this biocontrol product. Applications should be timed around the period of egg laying to ensure that the product is present on the crop as eggs hatch and larvae migrate to a fruit entry point.

The application window for a codling moth control insecticide starts post-blossom when the fruits are developing on the trees. This is a key period for pear psyllid (C. pyricola and C. pyri) management as natural populations of Anthocoris spp. are moving into the orchards to feed on pear psyllid and number of both are increasing in the warmer weather. Application of a codling moth specific product such as Madex Top does not affect the Anthocoris spp. therefore allowing them to increase in numbers to manage the psyllid population.


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 non-target organisms so not disrupting the food web of the pear orchard ecosystem which keeps populations of other potentially damaging pests (such as pear sucker C. pyricola) under control.

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