Evolution of egg-laying potential and number of eggs of pear psylla Psylla pyri (L.), (Hom., Psyllidae) during winter and spring periods, in the lower Rhone valley
1988
Lyoussoufi, A. (Institut National de la Recherche Agronomique, Montfavet (France). Station de Zoologie et d'Apidologie) | Rieux, R. | Arcier, F.F. d'
The egg counting in orchard is an essential element in populations dynamics studies of Psylla pyri (L.). Yet, it partially reflects the actual number of laid eggs, a part of which escape any counting, because of various causes. An attempt to find out this number was made by estimating the egg-laying potentialities of P. pyri. Female samples were weekly dissected and their mature ovocytes counted. Winter and spring populations show very high egg-laying potentialities (maximum 2527 eggs), allowing an important and early multiplication of pear psylla (rate about 9), from a very low population number. This study shows the advantage of an early control strategy of the winter-spring populations of the pest, even if their numbers seem to be low
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