Premium
FURTHER OBSERVATIONS ON THE PREVALENCE AND HABITS OF OSCINELLA FRIT , LINN.
Author(s) -
CUNLIFFE NORMAN
Publication year - 1924
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1924.tb05693.x
Subject(s) - biology , imago , larva , pupa , population , receipt , demography , toxicology , ecology , sociology , world wide web , computer science
Summary.1 Observations on the prevalence of the imago of Oscinella frit in the field have been made during the period 1919 to 1922. 2 The annual cycle consists of three generations: Generation III swarms from the end of April to the middle of June, with a maximum about May 26; Generation I from the end of May to the middle of August, with a maximum about July 15; Generation II from the end of July to the beginning of September (or longer) with a maximum about August 19. 3 Although meteorological variations during the period 1919 to 1922 were apparently very diverse, they were not sufficiently diverse to affect the prevalence periods of the fly on the crop materially; the prevalence curves of the different years show a remarkable similarity. This may be due to the fact that the larva is an internal feeder. 4 As the periods of maximum prevalence are not displaced from year to year, it would appear that the fly population is determined by the total number of host plants and not by the cultivated plants alone. 5 The larva exhibits a strong tendency to attack those regions of the plant which are in receipt of abundant supplies of sap.