Stored Grain Insects
Seed stored for more than six weeks must be protected against insect damage. Seed should only be stored when ‘dry’, as grain of high moisture causes temperatures to rise and mould to develop. High temperatures reduce the efficacy of grain protectants, allowing insects to multiply. Cooling of grain (below 15 degrees C) helps to suppress insect activity.
Insecticides applied to uninfested grain will protect against pests developing and damaging the grain (for a specified duration). Application of seed treatment insecticides after infestation and their over-use is discouraged. Such management facilitates the development of resistance to the chemicals within the insect population. Additionally if an infestation is current, seed treatment insecticides will assert little control.
Some Hannaford seed treatment products contain cypermethrin or triflumuron insecticide. Both insecticides protect against a range of insect pests of stored wheat, barley, oats and other small grains. Existing adult insects will die after ingesting cypermethrin; while triflumuron, an insect growth regulator, will kill any emerging larvae. Triflumuron will not destroy adult insects. Infested grain will therefore suffer insect damage before triflumuron acts upon the larvae as the insect life cycle proceeds.
Adults are dark brown and range from 2.0-3.5 mm in length. They are easily distinguishable from the borers and beetles by their long snout, characteristic of the true weevils. Females produce from 200-300 eggs in their 2-3 month lifespan. Adults cannot fly and feign death if disturbed. Eggs are deposited in whole kernels of grain; emerging larvae feed on whole grain. Adults feed in and on whole and broken grain.
As for the granary weevil, although distinguished by the four orange-reddish patches on its body.
Attacks oilseeds and cereals. Adults have a wingspan of 20 mm; the outer portion of the forewing is reddish-brown and the inner portion creamy-white. Eggs are laid on the surface of the grain.Larvae spin webs on the surface of the grain and consume kernels within the webbing.
This pest is capable of infesting all small grain and develops more rapidly in damaged than in whole grain. Adults are dark brown and range from 2.5-3.0 mm in length. Females produce between 200 and 400 eggs in their 2-3 month lifespan. Eggs are laid on the surface of the grain and larvae burrow into the kernels. Adults can fly, and also feed on the grain.
Capable of infesting both whole grain and oilseeds, but a more serious problem in stock feed and processed grain (ie flour). Adults are reddish brown and range from 2.3-4.4 mm in length. Females produce from 10-20 eggs per day, and over a lifetime of 200 days – 2 years, produce more than 1000 eggs. Larvae and adults feed on broken grain and flour.
Infests a wide range of commodities, but does not readily breed in whole grain. However, most samples of grain contain enough broken fragments for the beetle to become established. Adults are brown and 2.5-3.5 mm long with characteristic tooth-like projections on either side of the thorax. Adults may live for several years and females produce an average of 375 eggs. Larvae and adults feed on broken grain and flour.
Attacks cereal grain and oilseeds. Adults are grey with a dark band across the middle of the forewing. They have a wingspan of 15 mm. The moths live for only two weeks, but during this period females may lay up to 250 eggs on the surface of the grain. Larvae spin webs on the grain surface and consume kernels within the webbing. Seed stored for more than six weeks must be protected against insect damage.