Earias Vitella Research Articles

Life tables for spotted bollworm, Earias vitella (Fabricius), on four species of cotton

Life-table studies were carried out for Earias vitella (Fab.) on four Gossypium species [ G. barbadense (Suvin), G. hirsutum (MCU 9), G. herbaceum (TKHe 44) and G. arboreum (K 8)]. Life-table analyses revealed that maximum survival from egg to adult occurred on MCU 9 compared with other varieties. Net reproductive rate ( R 0) was also maximum on MCU 9 and minimum on K 8. The intrinsic rate of increase ( rm), finite rate of increase (λ) and weekly multiplication (e rm.7 ) were maximum on Suvin and minimum on K 8. The population on reaching stable age distribution ( SAD) consisted primarily ( c. 99%) of immature stages in all the four species of cotton tested in this study.

Developmental studies ofAmrasca devastansDist. andEarias vitellaFabr. on different cotton varieties

AbstractEight cotton varieties, Bikaneri‐nerma, CBS‐156, C‐Indore‐1, Hybrid‐4, Khandawa‐2, SRT‐1 (Gossypium hirsutumL.); Digvijay (G. herbaceumL.) and Suvin (G. barbadenseL.), were screened against jassid,Amrasca devastansDist. and spotted bollworm,Earias vitellaFabr. The test insects were reared, and their development on different host‐varieties was studied. The development ofA. devastansnymphs to adults on Digvijay, a hairy variety, was slowest of all the varieties tested; the nymphal survival to adult stage was also the lowest. Fastest nymphal growth was observed on smooth‐leaved variety, Suvin. The growth and development ofE. vitellalarvae was the best on long staple varieties, CBS‐156 and Hybrid‐4. The superior medium staple variety, Bikaneri‐nerma, and the other short staple varieties, supported the bollworm poorly.ZusammenfassungUntersuchungen über die Entwicklung von Amrasca devastans Dist. und Earias vitella Fabr. an Baumwolle verschiedener VarietätenDie Entwicklung der BaumwollschädlingeAmrasca devastansDist. undEarias vitellaFabr. wurde auf den acht Baumwollsorten Bikaneri‐nerma, CBS‐156, C‐Indore‐1, Hybrid‐4, Khandawa‐2, SRT‐1 (Gossypium hirsutumL.), Digvijay (G. herbaceumL.) und Suvin (G. barbadenseL.) untersucht. Die Entwicklung der Nymphe zum adulten Tier verlief am langsamsten und mit der niedrigsten überlebensrate beiA. devastansauf Digvijay, einer stark behaarten Varietät. Das schnellste Nymphenwachstum wurde dagegen auf der glattblättrigen Varietät Suvin beobachtet. Wachstum und Entwicklung vonE. vitella‐Larven waren optimal auf den langfasrigen Sorten CBS‐156 und Hybrid‐4. Die mittelfasrige Sorte Bikaneri‐nerma sowie die erwähnten kurzfasrigen Sorten erwiesen sich als schlechte Wirtspflanzen fürE. vitella.

EFFECTS OF THE CHEMOSTERILANT THIOTEPA ON THE PEA APHID, ACYRTHOSIPHON PISUM (HOMOPTERA: APHIDIDAE)

In an evaluation of several chemosterilants for insect control Borkovec (1972) stresses their safe handling. The compound tris (l-ziridinyl) phosphine sulphide, trivial name thiotepa, is currently being tested as a sterilant against several insects. More recently, Terry et al. (1977) noticed a 99 to 100% sterility in boll weevils treated with thiotepa. When 0- to 24-h-old pupae of Trogoderma granarium Everts were dipped in 1% thiotepa for 8 min only 0.1% of their eggs hatched (Chaudhary and Kapil 1977). The males of Earias vitella F. were also sterilized when their pupae were dipped in 0.5 to 0.75% thiotepa (Singh et al. 1978). Finally, no eggs hatched when Dysdercus koenigii (F.) was topically treated with 4 pg of thiotepa per insect (Govindan and Pillai 1977).