Page 36 - ALG Issue 2 2018 html

Expert guide to...
Biological Pest Control on the Allotment
Ladybird larvae
Careful gardeners who manage their plots in a way that encourages insect predators will benefit from natural biological pest control.
A plot with a healthy population of ladybirds, hoverflies, lace wings and their larvae will have some aphids but the natural predators will keep them to manageable numbers. One lacewing larvae can get through more than 100 aphids an hour; they also
take part? We would love to hear how it went. Email marketing@ nsalg.org.uk if you have anything to report. There are also nematode treatments for caterpillars, vine weevils and codling moths and a combined treatment containing a mix of nematodes for cabbage root fly, cutworm, onion fly, sciaridae, gooseberry sawfly, thrips and caterpillars. It is recommended that these are applied every 6 weeks,
attack caterpillars and insect larvae, piercing them
and sucking out the juice. Plants that encourage
beneficial insects are coreopsis, cosmos, yarrow,
goldenrod, Queen Anne’s lace and marguerite
daisies. It is also possible to purchase ladybird and
lacewing larvae between late April and August, and
you can encourage them to breed and overwinter by placing insect hotels on your plot.
There are also biological controls that we can introduce into the allotment plot. The North West region of the Society has just taken part in a trial of pathogenic nematodes to control slugs. Did you
One lacewing larvae can get through more than 100 aphids an hour
which could prove quite pricey!
Biological controls work best in controlled
environments such as a greenhouse or polytunnel. Whitefly Control uses a tiny parasitic wasp called encarsia formosa. These are supplied as pupae on cards and hung in a shady position amongst your tomatoes and cucumbers. Spider mite can
be controlled by a predatory mite called phytoseiulus persimilis; this can be used outside if the weather is warm enough. Most biological controls need to be applied at specific temperatures and used as soon as they arrive. Take note - you must only use once the pest is visible or the predator will have nothing to eat and die!
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Yarrow
Lacewing