The study of oleander scale (Aspidiotus nerii Bche) and the way of diluting its entomophages in Azerbaijan

Abstract

Scales (Hemiptera, Diaspididae) are the dangerous crop and park-ornamental plant pests. They reproduce very quickly and cause great harm to plants, sometimes even lead to their complete destruction. Scales suck juices from plants, cause premature drying, dying and falling off leaves, dry branches, deformation of leaves, fruits and shoots, reducing annual growth of plants. Therefore the fight with these pests is rather topical in the agriculture. In this connection in this work the analysis of bioecological peculiarities of oleander scale on the territory of Azerbaijan, and also the detection of species content of parasites and predators, which regulate their number is conducted. We will mark that oleander scales in the wild there are the entomophages are vermin and predators that reduce their quantity. For realization of biological fight against people we studied the bioenvironmental features of wreckers, and also educed specific composition of vermin and predators that regulate their quantity. In a biological fight against these wreckers, one of basic questions is study of specific composition of these entomophages. The faunistic material on entomophages of this pest was collected from different biocenosis; the researched works were conducted in the laboratory and field conditions in Azerbaijan. The advanced and research studies that we conducted gave an opportunity to educe entomophages oleander scale that inflicts an enormous damage to the agricultural cultures and park-decorative plants. The method of breeding of effective types of entomophages is studied in laboratory terms. Firstly the biology of oleander scale on Apsheron peninsula and in Guba Khachmazskii area was studied. The results of long-term studies showed that oleander scale, having distributed on Apsheron peninsula, on olive trees gives 3 generations. Only adult female animals and maggots of I and II age spend winter. Awakening of the scales on olives takes place in March-April. In II and III decade of April the male animals begin their flight. In Guba Khachmazskii area the biology of this scale, dwelling on oleander bush was studied. On this plant the scale gives 3 generations. Young female animals, and also maggots of I and II age winter. As a result of the works conducted the following entomophages of oleander scale were detected: predator Rhyzobius lophanthae Blaisd, Chilocorus bipustulatus L., Chilocorus renupustulatus L; parasites: Aphytis chilensis Howаrd, Aspidiotiphagus citrinus Graw, Encarsia aurantii (Howard). The habitat of Rhyzobius lophanthae is Australia. At the end of the last century of this predatory beetle left to California, from there left to Italy and in other Mediterranean countries. In 1947 by chance was left to Georgia (Abkhazia). Maybe these useful predators in Azerbaijan were from Georgia. For diluting the entomophages from the local indigenous fauna the potato tubers were used, on which firstly the oleander scales, and then road-beetles Rhyzobius lophanthae, Chilocorus bipustulatus reproduced themselves. In the laboratory conditions the methods of diluting of these Coccinellidae was developed. Thus, firstly the way of diluting parasites of oleander scale was studied and developed – Aphytis chilensis Howard, Aspidiotiphagus citrinus Graw и Encarsia antantii (Howard). It was detected that predatory entomophage-chilocor in the natural conditions is ineffective, as their maggots and chrysalises are affected by other local parasites. In the laboratory conditions this beetle produce itself very well on the potato tubers, infected by oleander scale. However, we should note that among entomophage parasites Aphytis chilensis plays the huge role in destruction of scales. In dependence on the weather conditions this macrophage in the nature can give 3–4 generations. Also it was proved that beetle Rhyzobius lophanthae in the biological fight can be applied against all round scales. This predator is effective entomophage of oleander, olive scale, black pine-leaf scale, white peach scale, European fruit scale and cactus scale. In connection with this, Rhyzobius lophanthae can be applied in the biological fight against oleander scale and presently is irreplaceable and perspective entomophage.