THE BIOLOGICAL CYCLE OF THE PLUM MEALY APHID (Hyalopterus pruni Geoffr.) ON THE CLIMATIC CONDITIONS FROM S.D. BANU MĂRĂCINE, CRAIOVA

Abstract

The plum mealy aphid Hyalopterus pruni Geoffr. is one of the main pest of the plum orchard at the S. D. Banu Maracine. An important link for controling this pest is the knowledge of the biological cycle, in order to establish the best moment for the treatments. 
 The plum mealy aphid is an migratory species, with an holocyclic, dioecious development. This species produce damages in the plum orchard from Europe, Asia and northern Africa. The main host plant is the plum tree or other species belonging to the Prunus genra and as secondary host the plum mealy aphid prefere different graminaceae species as: Phragmites, Calamagrostis, Agrostis, etc.
 The research regarding the biology and ecology of the plum mealy aphid has been made at the Didactical Station Banu Maracine, Craiova, in a plum orchard, Stanley variety.
 During the 3 years of research the period for layings eggs has oscilated between 23 days in 2004 and 31days in 2002.The development of the fundatrix, has been framed between 24 days in 2004 and 29 days in 2003. In 2002 the development of the fundatrix has been completed after 26 days.
 During the climatic conditions of 2002-2004, there has been developed 4 generations of wingless aphid (2002 and 2004), respectively 5 generations in 2003. These 4, 5 generations have phased from the second or third decade of April untill the second half of July. 
 From our observations regarding the development on the secondary host plants, it come out that the first generation has completed it development, function the climatic conditions, in 7 to 11 days. There has been phased 8-9 generations of winged and wingless form, untill September and even October. The last generation has ensured the appearance of the sexuparae form, which has migrated in the plum orchard and give birth to the sexuale forms. 
 The laying of hibernating eggs, begun in October, phasing to the first decade of November.