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Báo cáo khoa học: "Biology and ecology of Elatophilus nigricornis Zetterstedt (Hemiptera Anthocoridae) predator of Matsucoccus feytaudi Ducasse (Homoptera Matsucoccidae) in the South-East of France"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: Biology and ecology of Elatophilus nigricornis Zetterstedt (Hemiptera Anthocoridae) predator of Matsucoccus feytaudi Ducasse (Homoptera Matsucoccidae) in the South-East of France. | 777 Ann. For. Sci. 57 2000 777-792 INRA EDP Sciences Original article Biology and ecology of Elatophilus nigricornis Zetterstedt Hemiptera Anthocoridae predator of Matsucoccus feytaudi Ducasse Homoptera Matsucoccidae in the South-East of France Jean-Pierre Fabrea Pierre Menassieub Jean-Jacques Foinga and Alain Chalona a Unité de Recherches Forestieres Méditerranéennes INRA av. Vivaldi 84000 Avignon France b Laboratoire d Entomologie Forestière INRA Pierroton BP 45 33611 Gazinet Cedex France Received 23 December 1999 accepted 26 May 2000 Abstract - The pine scale Matsucoccus feytaudi was accidentally introduced into the maritime pine stands of the Maure and Estérel Forests. It is the primary cause of the dieback of 120000 ha stands and its specialist predator Elatophilus nigricornis has been studied. It is possible to maintain and raise it in laboratory conditions but its output is not prolific enough to envisage propagation which would allow it to be released in natural conditions. When raised in laboratory conditions the time required for its development table II and fecundity have been determined. In natural conditions nymphs develop in trunk bark cracks adults mate but females insert eggs in needles. The population of the eggs is distributed according to two gradients a decreasing gradient from the bottom to the top of the trees and a decreasing gradient from the trunk to the extremities of the branches figures 3 and 4 . The distribution of its nymph populations on the trunk and branches is different before figure 5 and after figures 6 and 7 the invasion of M. feytaudi. In reality the distribution of the predator nymph populations always coincides with that of its host even when that of the latter changes. E. nigricornis produces at least three generations a year one for M. feytaudi and overwinters at the fertilized female stage figures 1 and 2 . Two sampling methods have allowed us to estimate the population levels which have developed during figure 8 table III