Major natural enemies of Durian insect pests

Natural enemies of Durian pests are essential in keeping pest populations at low levels. There are three distinct types of natural enemies: predators, parasitoids, and pathogens.

Predators

Common predators found in Durian include lacewings, ladybird beetles, spiders, Dolichopus sp., predatory mites, and predatory thrips.

Lacewings: Chrysopids

Lacewings are insects belonging to the family Chrysopidae (order: Neuroptera). Their larvae, and in some species also the adults, are predators of other insects. They feed on aphids, spider mites (especially red mites), thrips, whitefly, insects eggs, small caterpillars and larvae of beetles.

In Durian, lacewings are found as predators of durian psyllid, mealybugs and scale insects.

For more information see: Lacewings

Ladybird beetles (Coccinellidae)

Ladybird beetles are also called "coccinellids", "coccinellid beetles ", "ladybugs" or "lady beetles". They belong to the family Coccinellidae.

There are many species of coccinellids and a big number of these are predators of other insects. In these predaceous species, both the larvae and the adults are predators, feeding on aphids, mites, whiteflies, small insects, insect eggs, etc.

There are also a number of coccinellids that feed on plants. For example Epilachna spp. feed on plants and can sometimes become pests in eggplant or other crops.

In Durian, larvae and adults of coccinellids are important as predators of durian psyllid, mealybugs and scale insects. Another coccinellid (Stethorus sp.) feeds on African red mite.

For more information see: Ladybird beetles

Spiders (Araneae)

Spiders are predators of a wide range of insect pests including aphids, mites, moths, flies, beetles, etc. Some spiders catch their prey by hunting for them, while other spiders use webs to catch flying prey insects.

In Durian, spiders are important as predators of durian psyllid, fruit borer, seed borer and other moths.

For more information see: Spiders

Dolichopus sp. (Diptera)

Long leg flies (Dolichopus sp.) are predators of the African red mite.

Predatory mites

Not all mites are crop pests. Some mites are predatory and feed on other mites. For example the predatory mite Amblysius longispinosus can control the African red mite.

For more information see: Predatory mites

Predatory thrips

Not all thrips are harmful to the crop. Some thrips species are predators that feed on other thrips.

Parasitoids

Parasitoids that act as natural enemies of durian pests include: Cotesia sp. and encyrtids.

Cotesia sp.

Synonym: Apanteles sp.

Cotesia species are larval parasitoids found for example in Durian fruit borer and in the stalk eating caterpillar. They belong to the Braconids family (Order: Hymenoptera, Family: Braconidae).

The genus Cotesia contains many species of natural enemies, which are natural enemies of many pests of fruits and vegetables. Female wasps lay eggs inside a caterpillar where the larvae of the wasp will then develop. This caterpillar may continue to live for some time, but eventually it dies. When the larvae finally emerge from the caterpillar they pupate in small silken cocoons that are usually found on or near the dead caterpillar.

Conservation

Cotesia species are very sensitive to pesticides and will quickly disappear when chemical insecticides are used. To conserve Cotesia it is therefore important to avoid using insecticides when possible.

If insecticides are used, this could even result in an increase of pest insects because their natural enemies are killed.

Encyrtids

Encyrtids are tiny wasps belonging to the family Encyrtidae (Order: Hymenoptera). Many encyrtids are endoparasites of scale insects or mealybugs, but other species attack also caterpillars and beetles. In Durian, encyrtids help the control of Durian psyllid.

Pathogens

Fungal pathogens that help controlling durian pests include Hirsutella sp., Beauveria bassiana, and Trichoderma harzianum.

Hirsutella sp.

Beauveria bassiana

Trichoderma harzianum

Fungus antagonist of other fungi including Phytophthora palmivora and Rhizoctonia sp.

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