Biology of subterranean populations of woolly apple aphid, Eriosoma lanigerum (Hausmann)(Homoptera:Aphididae), in apple orchards

Content Provider	Semantic Scholar
Author	Damavandian, Mohammad Reza
Copyright Year	2000
Abstract	A study was made of the basic biology of subterranean Eriosoma lanigerum (Hausmann) populations in apple orchards in the Western Cape Province of South Africa. The absence of cornicles and the presence of a vulva could be used to identify 1st instar nymphs and adults respectively. Body length, body width and length of the hind femur are useful for separating 2, 3 and 4 instars. However, separation of 2 from 3 instar nymphs was very unreliable. Maximum population growth rate was at 23°C while at 30 °C population growth was zero. The estimated minimum and maximum threshold temperatures for development were 4.32 and more than 30°C respectively. Numbers of underground E. lanigerum in soil samples taken using mechanical and hand augers were similar. However, numbers of aphids in samples were influenced by the distance from the trunk at which the samples were taken and the presence and the type of root material in the samples. More aphids were recorded close to the trunk, and at a given distance from the trunk more aphids were recorded if there was root material in the sample, especially if the roots were galled. Stellenbosch University http://scholar.sun.ac.za
File Format	PDF HTM / HTML
Alternate Webpage(s)	http://scholar.sun.ac.za/bitstream/handle/10019.1/51638/damavandian_biology_2000.pdf;jsessionid=368B077DC310B767B887396033D69085?sequence=1
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article