The poinsettia strain of the cotton whitefly,Bemisia tabaci(Homoptera: Aleyrodidae), biological and demographic parameters on poinsettia (Euphorbia pulcherrima) in relation to temperature

Abstract

Biological characteristics of the poinsettia strain of Bemisia tabaci Gennadius were investigated on poinsettia by laboratory experiments at five temperatures (range: 16°C-28°C). In addition, the effect of rearing B. tabaci on the two plant species, Nicotiana tabacum (tobacco) (Solanaceae) and Euphorbia pulcherrima (Euphorbiaceae) (poinsettia) was investigated. The temperature-dependencies were established for the developmental time for eggs and egg-to-adult phase, juvenile mortality, adult female life-span, pre-oviposition period, age-specific fecundity, and sex-ratio. The lower temperature thresholds for egg-development, development from egg to adult and for ovipositional adults were estimated as well as the lower temperature threshold for oviposition. The thresholds were 12°C, 14°C, 8°C and 14°C, respectively. Egg-development required 126 day-degrees and the entire development into adults 327 day-degrees. Mortality was highest at 16°C, being 19.3% in the egg-stage and 95% from egg to adult. The pre-oviposition period and the adult life-span were 40 and 360 day-degrees. The age-specific fecundity of B. tabaci was described by a temperature-dependent model. The maximum daily fecundity rate was attained after 60 and 125 day-degrees for B. tabaci reared on tobacco and poinsettia, respectively. The fecundity was highest for B. tabaci reared on poinsettia. The sex-ratio was in favour of females at and above 19°C and increased with temperature. Estimates of the net reproductive rate, the intrinsic rate of increase, the finite rate of increase, the mean generation time and the doubling time were obtained. A positive linear relationship was found between r m and temperature, the values ranging from 0.0012 at 16°C to 0.1263 at 28°C.

Biological traits and Life table parameters A and B biotype of Bemisia tabaci (Genn.) on cotton and rapeseed

“…Certainly, all values of r m for B. argentifolii, which were recorded by Liu and Stansly (1998), Yang and Chi (2006), Kakimoto et al (2007) Luo et al (2008 and this work showed that H. rosa-sinensis and cotton were poor hosts for B. argentifolii in comparing with other hosts such as eggplant, tomato, sweet potato, cucumber, garden bean and rapeseed. Based on the present findings, the fecundity of B biotype (68 eggs) reared on rapeseed was higher than on cotton (51.2 eggs), but it was lower than on poinsettia (85.0 eggs) (Bethke et al 1991) and tobacco (72.3 eggs) (Enkegaard 1993) at about 25ºC. Yee and Toscano (1996) reported the range of 40.6 -70.6 eggs for alfalfa, broccoli, cantaloupe, zucchini and cotton at 27°C.…”

“…The developmental times of B biotype (22.28 d) reared on cotton in this study were nearly equal to those reared on cotton (23.6 d) and poinsettia (23.2 d) at about 25ºC (Bethke et al 1991) and on sweet pepper (21.5 d) at 26ºC (Muniz and Nombela 2001). The fecundity of B biotype reared on rapeseed (68 eggs) was higher than on cotton (51.2 eggs) (Bethke et al 1991) and less than on poinsettia (85.0 eggs) (Bethke et al 1991), tobacco (72.3 eggs) (Enkegaard 1993) at about 25ºC, and on alfalfa, broccoli, cantaloupe, cotton and zucchini (40.6 -70.6 eggs) at 27ºC (Yee and Toscano 1996). This study demonstrated that the type of host plant had a significant effect on the development, survival and reproduction of B and A biotype.…”

“…These findings generaly agreed with other related studies about these whitefly biotype (Coudriet et al 1985;Bethke et al 1991;Powell and Bellows 1992a, b;Enkegaar 1993;Simmons 1994;Yee and Toscano 1996;Nava-Camberos et al 2001). Enkegaard (1993) recorded values of r m , λ, T and DT for the B strain of B. tabaci (= B. argentifolii) at 25º on poinsettia plants as 0.087, 1.091, 43.0887 and 7.94, respectively. These values were less than those found for B biotype reared on cotton and rapeseed in the current study.…”

“…In addition both adults and nymphs excrete honeydew, which can promote the growth of sooty moulds, which affect the market price of the product, and reduce plant photosynthesis and effectiveness of insecticides (Gerling et al 1980;Palumbo et al 2000). Main factors of regulating the whiteflies biology and population dynamics are temperature (Enkegaard 1993;Cui et al 2008;Guo et al 2012), host plant suitability (Yano 2003;Kakimoto et al 2007), natural enemies (Liu and Stansly 1998;Headrick et al 1999;NavaCamberos et al 2001) and management practices (Musa and Ren 2005). However, chemical control approaches are still valuable integrated pest management (IPM) tools that help to maintain or improve crop yield.…”

The life table of the lucerne beetle, Gonioctena fornicata (Brüggem) (=Phytodecta fornicatus Brüggem) (Coleoptera, Chrysomelidae) on alfalfa under laboratory conditions

“…The Age-specific number of eggs laid by a female during the oviposition period was described by the Enkegaard equation: (-b.x) (Enkegaard ,1993;Hansen et al, 1999) where F(x) is the Daily age-specific fecundity rate (eggs/female/day), x is the female's age in days, a and b are constants. Day 1 is the first day of the oviposition period.…”