ISHS Acta Horticulturae 591: III International Symposium on Pistachios and Almonds
THE IMPORTANT BEETLE PESTS OF THE PISTACHIO TREES IN IRAN |
| Author: | H. Farivar-Mehin |
| Keywords: | Pistacia vera, Hylesinus vestitus, Capnodis cariosa hauseri, Polydrosus davatchii |
| Abstract:
The beetle insects are among the important pests of the pistachio trees in Iran. Three species of the beetle belonging to families Scolytidae, Buprestidae and Curculionidae (Coleoptera), cause considerable damage to pistachio trees, Pistacia vera L. The pistachio twig borer beetle, Hylesinus vestitus Mulsant & Rey (Col.: Scolytidae) is known as an injurious insect. It is distributed throughout the pistachio growing areas of the country. The adult beetles appear in pistachio orchards from late March, and attack pistachio buds. The beetles feed upon tree buds and bore a short cave (channel) in twigs (about 4-5 cm deep) just beneath the buds. This species almost always attacks healthy trees for feeding, during the spring and summer, and therefore the beetle destroys the buds (either fruit or vegetative buds). Usually the beetle attacks a single bud for the whole spring and summer period, but sometimes each beetle causes damage to 2-3 buds too. The beetles stay inside the cave until early October and then emerge to seek ovipositing sites. They choose the damaged, pruned or dead pistachio twigs, branches and trunks either inside or outside the pistachio orchards for ovipositing. This species produce one generation per year. The most effective control technique is collecting and removing all of the damaged and dead pistachio twigs and branches, and then burning them to prevent proper oviposition sites for adults. The pistachio root beetle, Capnodis cariosa hauseri Ob. (Col.: Buprestidae), is usually assumed to be a pest of old pistachio trees but it attacks the young trees as well. This insect was distributed in many pistachio growing regions of Iran and causes heavy damage to pistachio trees, particularly when the infection is accompanied by gummosis. The pistachio root beetle usually emerges in the early spring and lays eggs on the pistachio trunk as well as around the pistachio collar. However, it was found that a part of the beetle population appears in the early autumn, and may overwinter and then reproduce in the following spring. The newly hatched larvae bore into the trunk close to the collar and then continue towards the roots. It causes general weakness in the pistachio trees and may even kill the infected trees. The pistachio weevil, Polydrosus davatchii Hoffman (Col.: Curculionidae), is found in some pistachio growing areas of the Kerman province. The adult weevils appear in the pistachio orchards in early spring when the flowering buds start to open. The beetles feed upon and destroy several buds, flowering clusters and tiny young fruits; therefore the weevil damage is considerable in the contaminated areas. The pistachio weevil produces just one generation per year in pistachio orchards, and the beetle larvae are not assumed to be a pistachio pest. | |
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