Here at Harrod Horticultural we're a friendly lot, always willing to help - with organic solutions and biological control measures of course - with any gardening queries we receive; and we get sent a lot!
Of course, having our own Kitchen Garden is a major help as, unfortunately, many of the pests, diseases and problems you write/mail/call in about, we've got - or had - too!
Wireworms, and their potential to devastate potato crops and many other garden vegetables and plants, were in the forefront of this gentleman's mind - so here's the advice our horticulturist Martin Fiddes gave him...
Many thanks for your recent enquiry regarding the control of wireworms. These soil dwelling pests – which rather worryingly can live in the soil for up to 5 years - are the larvae of various species of click beetle. The wireworms found in garden situations are likely to develop into the garden click beetle or common click beetle.
The first stage of growing crops without the threat of wireworms is prevention. The female click beetles lay their eggs in June and July and these clutches hatch around a month later. The adult beetles prefer to lay eggs in grassy or weed-strewn sites so good husbandry on the plot is essential.
Thorough cultivation, especially in March and April (you can still plant potatoes up to late May, even first earlies) should expose wireworms and they can be removed and destroyed or left for birds – rooks have a particular taste for them – and inter-row hoeing during the growing season will also bring larvae to the surface where they can be easily picked off by predators.
Wireworms feed actively in March to May and also in September and October, so it’s essential not to leave your maincrop potatoes in the soil for longer than necessary, as they are a sitting target. Careful crop rotation – ensuring susceptible plants are not grown immediately after each other – should be standard garden practice anyway, and you might want to try a rudimentary potato trap; simply place a piece of potato on a skewer in the soil before planting and hopefully the wireworms will tunnel in. You can then remove the piece of potato together with the pests inside!
Also worthy of consideration is the nematode heterorhabditis megidis, most commonly used for the control of chafer grubs. Although this nematode has not been specifically tested for control of wireworms (contrary to what other websites state), the producers of this nematode are confident a good degree of control can be obtained. You can apply these nematodes as long as the soil temperature is above 12 degrees C.