Microbial Insecticides

Microbial insecticides battle damaging insects by enlisting the aid of microscopic, living organisms—viruses, bacteria, fungi, protozoa, or nematodes. They are “unconventional” insecticides, but they can be applied in conventional ways—as sprays, dusts, or granules.

Microbial insecticides are essentially nontoxic. They also do not pose a disease risk to wildlife, humans, and other organisms not closely related to the target insect. In fact, they can be applied when a fruit or vegetable is almost ready for harvest.

Most microbial insecticides are toxic to a single species or group of insects, so you can often target a pest without the risk of killing beneficial insects in the process. Also, most microbial insecticides can be used in conjunction with conventional insecticides.

In a few cases, the microorganisms used in these products can become established in an insect population or its habitat. This means the insecticide can provide control for several weeks or seasons. On the other hand, if several types of insects are causing damage to your lawn or garden, a single microbial insecticide will not be able to handle them all. As a result, there is a limited market for some microbial insecticides, so these products are not widely available or are relatively expensive.

Another disadvantage of microbial insecticides is that heat, drying out, or exposure to sunlight reduces the effectiveness of several types of microbial insecticides. Therefore, proper timing and application are especially important for some products.

The most popular microbial insecticides in the United States are preparations of the bacterium known as Bt. Bacterial insecticides must be eaten by the pest to do their job. The most widely used Bt products are pathogenic and toxic only to caterpillars—the larvae of butterflies and moths. Other varieties of Bt are available to control Colorado potato beetle larvae and certain mosquito larvae.

Viruses also must be ingested by the insect. They often cause dramatic natural disease outbreaks among insect populations. But unlike bacterial insecticides, the development of virus-based insecticides has been limited. Some important pests for which viral insecticides have been developed include the gypsy moth, pine sawflies, and the codling moth.

Like viruses, fungi create natural epidemics among insect populations, often killing a high percentage of the population. Only a few fungal insecticides are currently available in the United States. One is the Bio-Path cockroach control chamber—a fungus is the active ingredient.

Protozoan pathogens infect a wide range of insects. Some of them can kill insects rapidly, but most of them are known for their chronic, debilitating effects on pests. Protozoan infections can shorten an insect’s life span, result in less feeding, and reduce the number of offspring.

Technically, nematodes are not microbial agents—they are multicellular roundworms. But, being nearly microscopic in size, they are used much like true microbial insecticides. On a worldwide basis, laboratory or field applications have been effective against more than four hundred insect species, including numerous beetles, fly larvae, and caterpillars.

НУБіП України Ф-7.5-2.1.6-24

НАЦІОНАЛЬНИЙ УНІВЕРСИТЕТ БІОРЕСУРСІВ ТА ПРИРОДОКОРИСТУВАННЯ УКРАЇНИ

Факультет Педагогічний

Напрям підготовки Філологія (переклад)

Форма навчання денна

Семестр 4-6 Курс4

ОКР «Бакалавр»

Кафедра романо-германських мов і перекладу

Дисципліна Практика письмового та усного перекладу

Викладач Сидорук Г.І.

«Затверджую»

Завідувач кафедри (Ніколенко А. Г.)

«»2012 р.

Дата добавления: 2015-07-10