15 May 1998

More mites in grain

BIG increases in mite infestation of grain highlight the need for good store hygiene, says Zeneca. The mild winter, muggy early spring and longer storage in poor facilities are all partly to blame for trade reports of increases in insect activity, it says.

According to Allied Grains Nick Oakhill the problem is occurring on farms where it has never been seen before.

Dalgetys Gary Hutchings says the pests have been particularly noticeable in barley going into intervention, where grain quality is rigorously policed. Grain for intervention must be fit for five years storage and that means being free of mites and other insects, he notes.

Mites can be effectively controlled by mixing an approved insecticide, such as Actellic (pirimiphos-methyl), into the grain surface, says Zenecas Jon Ogborn.

But where they are associated with other insect pests, treatment of the whole bulk is essential, he adds.

Effective prevention including pre-harvest store cleaning and disinfecting with Actellic spray and smoke generators is best, he says . "Infestations can be limited by effective drying and maintaining low store temperatures. Where long periods of storage are anticipated, growers would be well advised to treat the grain as it goes into store."

Assured Combinable Crops Scheme inspector Chris Duncan confirms the importance of pre-harvest cleaning, but reminds growers of the need to keep detailed records of pre-harvest treatments, such as smoke bombs and spraying, as well as any post-harvest applications already required on grain passports.

Records of regular monitoring of grain temperatures are needed under ACCS, but that should enable timely action to prevent costly insect build-ups, he notes. &#42