Barn weevil is one of the main and most dangerous pests of grain crops (barley, rice, rye, wheat, buckwheat, corn, as well as pasta), which can disrupt stocks on the scale of both the kitchen facilities and huge grain stores.
For farmers, its appearance is a disaster, because visually inconspicuous, the bug does huge damage to the crop.
Barn Weevil: Description
Characterized by small size (about 4 mm), the pest bug stands out with a dark brown, almost black color, a narrow long body and the presence of wings. Such an insect is not adapted for flying, which does not prevent it from successfully moving over considerable distances with the help of humans. On ships with industrial lots of grain, on land - by trains and cars, from one continent to another, a barn weevil travels. How to get rid of such a dangerous insect?
The process of reproduction of such insects occurs in the warm period: a female in each grain with a thin proboscis gnaws a small hole (two in the grain of corn), lays an egg in it, after which the cork from the flour covers the crack. Such a trick makes damaged grains externally practically indistinguishable from whole ones. One can distinguish a “catch” if a handful of grains are thrown into the water: damaged (populated) specimens will emerge, whole ones will sink to the bottom. At a visual inspection, you can see that grains with larvae are an order of magnitude dimmer in color than intact.
Barn Weevil Life Cycle
The fertility of one individual is 150-300 eggs with a life cycle of 3-4 months; males live a little longer, about 5 months. The duration of development of the larva (about 3 mm long, white, with a brown head) depends on temperature and humidity and is 3-6 weeks. One can only imagine how many thousands of pests only one pair of beetles can produce during the year. At a temperature of + 4 ° C, the larvae stop in development, at - 5 ° C they die. Upon completion of development, they turn into almost transparent, 3-5 mm long pupae. After 7 - 22 days, the formed beetles of a new generation gnaw out a passage in the shell and exit the shelter. The average life expectancy of an adult is about 2 years. During the day, one larva destroys 0.08-0.67 mg of grain, gnawing its internal contents; accordingly, the massive amount of these insects can destroy a significant amount of stocks.
Destroying a beetle in kitchen supplies
How to deal with such a dangerous pest as a barn weevil? How to get rid of such a small but harmful insect in the barn and in the kitchen? In the context of home stocks, when a weevil is found in cereals, the latter should not be eaten, because carcinogens are contained in the secretions of insects and larvae. Contaminated products must be discarded, and weevils must enter into a tough and, possibly, long-term struggle.
It is recommended to store cereals in jars or hermetically sealed containers - not in bags that the barn weevil (photo above) easily bites with his sharp teeth. Barn weevils are heat-loving creatures and die at low temperatures. Therefore, cold can be used as one of the ways to get rid of bugs: products that serve as potential food for weevils should be placed in the freezer. The tiny resident is destructively affected by high temperatures. So, at +40
the barn weevil dies within 2 days, at +50
- in 6 hours. After processing, food stocks should be placed in airtight containers with tight lids, inaccessible to insects.
Folk methods
Garlic, peeled off the husk and placed in a container with cereals, acts as a deterrent to the barn weevil. For preventive purposes, cabinets where food is stored must be treated with a soap-vinegar composition. On the shelves you can put bay leaf and lavender, the smell of which the weevil does not perceive. Large cereal stocks should not be made; products are best acquired as they are used.
Barn Weevil: Control Measures
It is very difficult to get rid of the barn weevil in warehouses , because the insect hides in hard-to-reach places, and being inside the grains is practically invulnerable and can destroy 10 to 30% of the harvested grain.
The fight against barn weevil consists in the following measures:
- Strong cooling of the grain (to -10 ° C), which can be used both for preventive purposes and in the process of destroying existing pests. Cooling is carried out in dry weather by ventilation and ventilation. At the same time, mandatory humidity control is required.
- Partially, the barn weevil can be eliminated by removing it on sieves with holes or using aspiration drugs. Any movement of the grain mass negatively affects the condition of harmful insects, reduces their number and development.
Chemical methods of weevil control
One of the effective methods of getting rid of barn weevil is chemical disinfection of grain - a radical measure consisting in aerosol or gas treatment. Aerosol disinfection is carried out with the help of “Actellik”, “Karate”, “Fufanon”, “Arrivo” preparations. This treatment, the advantage of which is the high efficacy of the drug, is performed by special organizations. The disadvantages of this method include a long period of time until the resolution of the sale of grain.
Gas disinfection is carried out by such drugs as Foskom, Alfos, Fostoksin, Magtoksin. Preliminary, the premises must be carefully sealed, and fumigation is carried out with the involvement of specialized organizations.
Prevention against Barn Weevil
It is important to observe preventive measures:
- Before falling asleep in silos, the grain must be cleaned of weed and grain impurities;
- separately store grain of different harvesting periods and different humidity;
- thoroughly clean containers from last year's grain and garbage stocks;
- monitor grain moisture (not lower than 14%); in the case of long-term storage, this indicator is recommended to be reduced by 2-4%, which enhances grain resistance to weevil damage and limits the vital activity of this pest;
- destroy contaminated stocks.
With severe infection, it will be necessary to fumigate the grain and storage facilities with the preparations intended for this.
As preventive methods, it is imperative to keep clean and tidy in warehouses, treat them chemically (using gas disinfection, aerosol and wet disinfection of warehouses), and whitewash before pouring grain.
Checking grain for infection with barn weevil should be done every 2 weeks in the summer and once a month in the winter. An infection test is carried out according to regulatory methods and standards.