Contribution to the study on red pear scale Epidiaspis leperii Signoret (Homoptera, Diaspididae) in Serbia

Abstract

Over 1991-1992, the presence of Epidiaspis leperii Signoret was monitored in the plantings and individual orchards at 19 localities in Serbia. The biology of the species was recorded on apple and pear at the Družetić locality. The intensity of the attack was determined according to the ocular fifth power system by Borhsenius (1963). The study proved Epidiaspis leperii to have one generation annually and to over winter as a sexually mature female. The longevity of specific stages in development and duration of a generation depend on temperature, relative humidity and precipitation Females began to lay eggs in late May of 1991, i.e. late April of 1992 Under our conditions, the stated period approximated 2 months, and one female lay on average 50 eggs. Mobile larvae appeared in early June of 1991 and mid May of 1992. Larvae of the second degree were recorded in mid-July of 1991 and late June of 1992. Young females appeared on the 10th August 1991 and the 21st July, 1992. Males were registered several days later. The development of females, i.e. males lasted 80-88 days, i.e 84-92 days respectively. Upon fertilization, females started diapause, and males died The presence of Epidiaspis leperii was recorded at 10 localities in pear plantings, i.e. at 4 localities in apple plantings with no regular control measures applied. It was not registered in the plantings with regular application of chemical substances. Red pear scale formed large colonies the estimation mark being 3 and 4, whereas it occurred individually or in small colonies on apple, the attack intensity amounting to 2 and 3 Epidiaspis leperii is a polyfagic species and a dangerous fruit pest primarily of pear, while it occurs sporadically on apple. In case of severe attack, it may cause withering of young trees, thus the control and adequate measures are a must.

U radu su prikazani rezultati dvogodišnjeg proučavanja bionomije crvene kruškine štitaste vaši, Epidiaspis leperii Signoret. Istraživanja su obavljena u zasadima kruške i jabuke u 19 lokaliteta u Srbiji. Uz detaljan opis vrste, dati su podaci o štetnosti, broju generacija i dužini razvića svih larvenih stupnjeva.