Identification and Biology of two Whitefly Species on Cassava in Sri Lanka

Abstract

A survey in four distant locations: Anuradhapura, Madampe, Sri Jayewardenapura and Uda Walawe of Sri Lanka to identify the whitefly species related to cassava revealed two species, namely Bemisia tabaci (Gennadius) and Alerodicus dispersus (Russell). The species B. tabaci was recorded in all four surveyed locations, while A. dispersus was collected only from the first three locations.The results of the study on the pest life cycle under the laboratory conditions showed that, B. tabaci and A. dispersus passed through four nymphal instars before the adult stage. The mean duration values of these stages were 7.2, 7.5, 4.7, 5.6 and 8.5, 6, 9, 9 days respectively for the two species. The total duration of the life cycle of B. tabaci ranged from 22-57 days at the temperature of 29±2°C with a mean of 37.5 while that of A. dispersus was 27-68 days with a mean of 48 respectively (at 28±2°C).The damage to crop plants caused by two whitefly species is discussed with a special emphasis on their ability to transmit viral diseases.

Characterization of cassava (<em>Manihot esculenta</em> Crantz) cultivars in Sri Lanka using morphological, molecular and organoleptic parameters

“…Recently, exporting of cassava tubers became an attractive industry in Sri Lanka due to the high demand especially from middle-east countries. So far, no studies have been carried out for cultivar discrimination even though there are several studies published related to disease identification in cassava cultivars (Jose et al, 2008;Kumarasinghe et al, 2009). Therefore, the present study was conducted to characterize the morphological, biochemical and molecular traits and, consumer preference of the cassava cultivars grown in Sri Lanka.…”

Biology and morphology of life stages of three species of whiteflies (Hemiptera: Aleyrodidae) from India

“…Bemisia tabaci has a host range exceeding 600 plant species and is a major vector of numerous plant viruses which have a great impact on agriculture worldwide. Russell (1975) compiled literature on the biology and morphology of B. tabaci and other whitefl y species on legume crops, and numerous studies on the biology of B. tabaci under diverse environmental conditions have since been published (Butler et al 1983;Coudriet et al 1985Coudriet et al , 1986Mohanty & Basu, 1987;Bethke et al 1991;Powell & Bellow, 1992;Salas & Mendoza, 1995;Thompson, 2000;Musa & Ren, 2005;Fekrat & Shishehbor, 2007;Kumarasinghe et al 2009;Carabali et al 2010; Thomas et al 2011). Dialeurodes delhiensis, a forest pest which infests Ficus sp., was described from Delhi, and until now nothing has been known of its biology.…”

A critical evaluation of the effects of plant essential oil formulations against silverleaf whitefly, Bemisia tabaci, B biotype (Gennadius) and its natural enemies

“…The pedicel is usually inserted in the stomatal opening and provides attachment and a supply of moisture to the egg (Byrne and Bellows 1991;Buckner et al 2002). Eggs could be laid singly or in small groups (Kumarasinghe et al 2009 (Martinez et al 2009). The number of eggs laid may vary depending on temperature and host plant.…”

“…The life cycle of B. tabaci B biotype depends on temperature and host plant (Sharaf et al 1985;Drost et al 1998;Bosco and Caciagli 1998;Chaudhuri et al 2001;Islam and Ren 2007;Kumarasinghe et al 2009). …”

“…evelopmental time of the nymphal stage was also measured and it took 73 days at 15 whereas it spent 12 days at 27.5 . Kumarasinghe et al (2009) (Kumarasinghe et al 2009). …”