Durian Psyllids
English name: Durian Psyllid
Scientific name: Allocaridara malayensis Crawford
Pest group: Insects
Order: Homoptera
Family: Psyllidae
Description and life cycle
| The adult lay the eggs into the tissues of young leaves. Eggs are found in clusters of 8-14 eggs as yellow or brown colored spots. The nymph that hatches from the eggs is very small (1 mm) while the second instar larva is about 3.0 mm long. Nymphs have white feather-like structures around the body, especially at the rear this long white fluff looks like a chicken's tail. The adult does not have these white structures, instead it has a greenish-brown body and is about 5 mm long. Adults do not often fly, except when they are disturbed. Both the nymphs and adults are usually found on the underside of the leaves. |  |
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Plant damage and plant compensation
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Psyllids attack the shoots of Durian, especially the young leaves during the flushing stage. Damage to the crop occurs when the larva and the adult of Psyllids suck juices from the leaves. As a result, the young leaves will have yellow spots and do not have a good development. With high populations, the leaves will become curly, get dry and drop off. Most damage is done by the larvae. Psyllid larvae also release honeydew, which is a sticky substance that covers the durian leaf. Fungi (sooty mold) may develop on this honeydew, which causes the leaves to turn black in color. The Chanee variety of Durian is very susceptible to damage by Psyllids. |
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Natural enemies
| Natural enemies of durian psyllids include several predators such as larvae
and adults of coccinellids (lady beetles), larvae of chrysopids (green
lacewings) and spiders.
Psyllids larvae are also controlled by parasitoids such as encyrtid wasps. Encyrtids are small wasps belonging to the family Encyrtidae. Especially in farms with low or no pesticide use, these parasitoids can be found in big number and are very important in the biological control of Durian psyllids. |
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Management and control practices
Prevention activities
 | Psyllids attack mainly the young leaves. By synchronizing the flushing, the infestation period will become shorter and damage by psyllids will be reduced. Flushing can be stimulated by foliar application of urea (46-0-0) at the rate of 200 gram in 20 liter water per tree. The first flushing can be timed during June-July after the first pruning. The second flushing will be during August-September after the second pruning |
| Regular monitoring of trees, especially during the period June to November is needed to observe the pest situation. |
What can be done when Psyllids are present in the field
| Yellow sticky traps can be used to attract and catch adults. |
| Water jet sprays can be used on opened young leaves. The spray will wash away nymphs and adults. |
| Chemical control of Psyllids is only needed when the attack is very serious. Earlier manuals on Psyllid management give economic thresholds recommending to spray chemicals when more than 50% of the shoots are infested (a shoot is infested if it has more than 5 living psyllids present). But before deciding to use synthetic pesticides it is essential to also closely observe the presence of natural enemies. To protect natural enemies it is always better to avoid the use of chemicals and instead try to control the pest with water jet sprays or other safe methods. |
| lambda-cyhalothrin (class II), carbosulfan (class II), carbaryl (class II), cypermethrin/phosalone (both class II)....look up effect on natural enemies. |
Points to remember about Durian psyllids
| Durian psyllids have many natural enemies which can keep populations low |