Most insect control methods for stored grain work against all species. So you don’t need to identify the storage pests to make decisions about most control methods.
But if you intend spraying grain with insecticides you may need to know which species are present if:
• a previous application has failed and you want to know whether resistance was the reason - if more than one species survived, resistance is unlikely to be the cause
• you intend using a residual protectant to treat infested grain – Actellic, Fenitrothion and Reldan are ineffective against lesser grain borer, and Actellic and Fenitrothion are generally ineffective against sawtoothed grain beetle
• you intend using dichlorvos to treat infested grain - if lesser grain borer is present you need to apply the higher dose rate.
Insecticide sprays are not registered for oilseeds and pulses, so identification of pests in those grains is not so important.
Cereal grains include wheat, barley, oats, triticale, sorghum and millets.
Lesser Grain borrer
The most common insect pests of stored cereal grains in World are:
weevils (the rice weevil is the common species in wheat)
lesser grain borer
sawtoothed grain beetle
flat grain beetles.
Pulses include: faba beans, chickpea, cowpea, field pea, mung bean, navy bean, soybean, pigeon pea. The most common insect pests of stored pulses are:
• bruchid beetles
Identifying the common pests
The common pests can be separated fairly easily into three groups:
• moths - moth larvae or grubs leave silken webbing on the surface of the grain, and the moths can be seen flying above the grain, particularly at dusk.
• bruchid beetles - if beetles in your stored pulses are leaving perfectly round holes where they emerge from the grains, you have bruchids
• other beetles - most of the beetle pests of stored grain are about 3 mm long, brown in colour and difficult to distinguish if you haven’t been shown how.
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