Technical Talk

Chemicals for controlling pests, diseases and weeks are some of the tools of our trade, the term pesticide can all to easily stimulate some emotive discussion on their use. There are howevber two other closely linked issues relating to tpesticides that do not seem to get as much debate and these are how to maintain an effective crop protection programme that it legal and cost efficient.

Everyone that has been through the Assured Produce Scheme audit (EUREP GAP for readers overseas) looks into their spray store and says how many of these chemicals are legal?

I have always relied upon the "Green Book" as the best guide to what is and what is not approved, but it suffers as all printeed texts do from becoming out dated and therefore inaccurate. Good news here - CSL have a very good website www.csl.gov.uk and a program called Liaison costing £120. This is updated daily and gives forwarnings of pesticides losing their registration and a searchable index for targets and pesticides.

If you list out all the active ingredients available to us as soft fruit growers it does look quite small and yes I have been tempted to say that we have far fewer chemicals available than we used to depending on how far back tou look, but the number of actives we have is not so far difference from 15 years ago. What is however very noticeable is there is still a big range of product available, chlorpyrifos is one active ingredient but sold as fourteen brands of the same liquid formulation from almost as many manufacturers. This competition is good for pricing but only up to a point! Surely?

I would rather see some of those 14 sets of costs from marketing, pesticide rgistration and distribution be focused on finding more effective ways of using the chemicals than we have. Take the example of thrips - we have two growers who were both suffering big problems last year, they both used the same strategy this and last year with a result that one growe has problems this year and the other is completely clear. Local conditions make a big difference to pest incidence and severity of attack as does crop rotation and any help from natural or introducwer predators. However a pest as difficult to control as WF Thrip requires a concerted effort to ensure the insecticide distribution distribution and timing are effective. While a protective spray for mildew is probably wasted on anything other than leaf and flower growth your spray for thrips could be as active on the beasts in the soil as they are on the plants.

We will be posting up regular technical information to our website on such matetrs as pesticides. The technical area is a clsoed site for group members, if growers are interested in a forum section to facilitate the exchange of information and experiences i.e. does anybody know how to control...pest/disease let us know.

Autumn 2002