The role of abiotic factors in the pupation of Thaumatotibia leucotreta Meyrick (Lepidoptera: Tortricidae) in the soil.
A key focus area of the South African citrus industry is the improved control of the phytosanitary citrus pest Thaumatotibia leucotreta (Lepidoptera: Tortricidae). New methods of control for this pest are continually being sought and the use of entomopathogens as biological control agents of the soil-dwelling life stages of T. leucotreta has shown great promise. Current understanding of T. leucotreta pupation biology, behaviour and survival is limited; thus, improving upon this knowledge would be useful for the biological control of this life stage. Abiotic factors, namely soil texture class, ground cover, soil compaction and soil moisture, were investigated in the laboratory, aiming to determine the effects of these on T. leucotreta pupation variables. The investigations consisted of an examination of the wandering behaviour of larvae prior to pupation site selection, the pupation behaviour after selecting a pupation site, and eclosion biology and success. These abiotic factors often had a limited influence on T. leucotreta pupation. Interesting consistencies included limited wandering behaviour, the shallowness of T. leucotreta pupation and a high eclosion success in sandy loam soils in certain cases. These factors are likely to have both positive and negative implications for entomopathogenic biological control programmes.