Think before you spray (From Gazette & Herald)

Think before you spray

WINTER wheat growers should think twice before rushing out to spray for orange blossom midge, according to Dave Robinson of The Arable Group (TAG). The unwarranted spraying of insecticides can be damaging to both farm profits and the environment, he says.

Mr Robinson, addressing a group of visitors to the Forward Farming demonstration at John Clappison's Whinhill Farm, at Ottringham near Hull, urged growers to carefully assess midge levels before spraying. In any case, it would not be economic to treat crops which had reached the flowering stage.

"Blanket-spraying of pesticides is likely to do more harm than good in the longer term by depressing populations of beneficial insects such as ground beetles. Aphid predators are likely to be seriously knocked back and that may necessitate further spraying, creating a vicious circle," said Mr Robinson.

The most important natural enemies of the midge are small parasitic wasps, which can give useful control. By not spraying below economic spray threshold levels, wasp numbers may increase and provide longer-term control.

Potentially damaging populations of midge larvae may be found in any field where wheat has been grown over the past five years. The more frequently wheat is grown, the higher the risk. With ADAS claiming that up to one-tenth of the UK wheat crop could be lost to orange blossom midge, it's hardly surprising that some farmers have been panicked into spraying unnecessarily.

The most effective pesticide, clorpyrifos, is now virtually unobtainable as growers seek to combat levels of the pest previously unseen in northern England.

Sticky traps positioned at ear height can be helpful in monitoring midge activity.

Trials suggest that chlorpyrifos timed correctly will give 90pc control, whereas pyrethroids offer only 50 pc control.

The best solution for the future is likely to come in the form of orange blossom midge-resistant varieties. The first resistant variety, Welford, has now gained HGCA recommendation and there are more in the pipeline.

The Forward Framing arable events are organised by Bishop Burton College near Beverley and further details are available from Bill Meredith on (01964) 553000.

Updated: 12:54 Wednesday, June 16, 2004