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Preventive Control

Natural enemies

Parasitoids

  1. Scelio fulgidus is the most important egg parasitoid wasps' species of locusts. It is a black wasp 3-5 mm long. The female burrows into the top of the locust egg pod with its long needle-like ovipositor where it lays 1 egg per locust egg. The wasp larva feeds on the locust egg killing the developing embryo. Some of the wasp adults remain inactive in the locust egg for a month or more before emerging and they are found when locusts or grasshoppers reach the adult stage (DA, 2001).

Parasites

  1. Parasitic female blowfly (Blaesoxipha spp.) deposits her eggs on the locust's larvae. The tiny maggot like larvae then bore into the host. The fully-grown larva emerges through the locust body wall and pupates in the ground. The parasite has several generations a year. It usually does not kill the adult locust, but a parasitized female may lay fewer eggs. Nymphs generally die following the emergence of the parasite (DA, 2001).
  2. Bee-fly (Trichopsidea oestracea) females scatter thousands of eggs on the ground or on standing dead woods or tree stumps or fence posts. The resulting larvae move around freely until they find a locust or grasshopper, which they enter, through the breathing hole. Only one larva develops inside each host. After emerging, it burrows into the ground. The parasitized locust usually dies when the fly larva emerges (DA, 2001).
  3. Tarsonemid mites are locust parasites living on the inside of locust breathing organs. Their eggs can be seen on the dorsal surface of the locust when its wings are expanded. The mites are found attached to the wings and bodies on old locusts (DA, 2001).

Nematodes

Amphimermis are important parasites of wingless grasshoppers. Their eggs are laid in the soil and hatching is stimulated by rain. The larvae go to the soil surface to find and penetrate a grasshopper or locust. They remain in the host for about 4-5 weeks retarding growth development of the host. The host is killed when the nematode emerges to return to the soil (DA, 2001).

Predators

  1. Birds
  2. Fowls
  3. Frogs
  4. Ground beetle
  5. Spiders
  6. Some people

Management and cultural practices

Keep permanent soil cover. This practice will discourage locusts and grasshoppers to lay eggs in the soil.

Early locusts' detection is a preventive control to avert plagues. However, there is no effective cultural control method known for swarm of locusts' infestation.
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