All about potatoes.pdf - Vegetableipmasia.org
All about potatoes.pdf - Vegetableipmasia.org
All about potatoes.pdf - Vegetableipmasia.org
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8.<br />
MAJOR NATURAL ENEMIES OF POTATO PESTS<br />
8.1.8 Other predators<br />
Other predators found in potato fields are dragonflies, crickets and red ants. These<br />
insects are highly abundant on potato crops that have not been sprayed with<br />
insecticides, and are suitably effective at controlling insect pest numbers. Predatory<br />
ability depends on the species and development stage of the predator and its prey.<br />
8.2 Parasitoids<br />
8.2.1 Parasitoids of leafminer fly<br />
A. Hemiptarsenus varicornis<br />
Adult insects are a kind of parasitic wasp. They have blue-green<br />
metallic bodies measuring 1.3-1.2 mm in length and have two<br />
pairs of wings. These parasitoids are commonly found on potato<br />
crops. This parasitoid specifically parasitizes leafminer flies<br />
when they are still in their larval form. The wasp lays eggs on<br />
the leafminer larva. After hatching, the parasitoid larva lives on<br />
the leafminer fly larva by sucking its body fluids. Host larvae<br />
growth is stunted and they often die. On potato crops, rates of<br />
parasitism can reach 70%, albeit mostly too late in the season<br />
after a lot of damage has already been done. This parasitoid is<br />
not that effective at controlling quantities of leafminer flies by<br />
itself, but is complementary in a diverse natural enemy complex<br />
in the potato field.<br />
Male<br />
Female<br />
B. Opius sp.<br />
Adult Opius wasps have black bodies, two pairs of wings<br />
and jointed antennae. Although it is not so common, this<br />
parasitoid is generally more effective than Hemiptarsenus.<br />
It also parasitizes flies in their larval and pupal stages. The<br />
larva and cocoons of this parasitoid live inside leafminer fly<br />
larvae and pupae. Parasitized larvae and pupae will die.<br />
Intensive use of insecticides on potato crops will cause<br />
very low levels of parasitism.<br />
C. Gronotoma sp.<br />
Adult insects have black bodies and jointed antennae that look<br />
like beads. This insect solely parasitizes leafminer fly larvae.<br />
Parasitoid larvae live inside the bodies of leafminer fly larvae.<br />
Parasitized leafminer larvae can pupate, but will not develop<br />
into adult flies.<br />
8.2.2 Parasitoids of other potato pests<br />
Other parasitoids are found not only on leafminer flies,<br />
but also on other insect pests, such as aphids, cluster<br />
caterpillars, potato tuber moth larvae or cabbage looper<br />
larvae. The appearance of mummified aphids is a clear<br />
indication of the presence of the common parasitoid,<br />
Dieretella spp. Another way to determine whether<br />
parasitoids are present is to remove insect pest larvae<br />
A HANDBOOK TO THE ECOLOGY AND INTEGRATED MANAGEMENT OF POTATO 51