Insecticidal activity and sublethal effects of Beauveria bassiana (Bals.-Criv.) Vuill. isolates and essential oils against Aphis gossypii Glover, 1877 (Hemiptera: Aphididae) | Insekticidna aktivnost in subletalni učinki izolatov entomopatogene glive Beauveria bassiana (Bals.-Criv.) Vuill. in eteričnih olj na bombaževo uš (Aphis gossypii Glover, 1877, Hemiptera: Aphididae)

Inglés. The cotton aphid, Aphis gossypii Glover, 1877, is a polyphagous species and one of the most important pests of cucumber crops in Iran. In this study, virulence of three Beauveria bassiana (Bals.-Criv.) Vuill isolates, IRAN 108, IRAN 429C and LRC 137, as well as insecticidal activity of two essential oils extracted from Matricaria chamomilla L. and Cuminum cyminum L. were evaluated against adult stage of A. gossypii under laboratory conditions. The data for life table were analyzed using the age-stage, two-sex life table theory. Results showed that all isolates were pathogenic on aphid, but their virulence was varied in different isolates. The lowest calculated LC50 was belonged to IRAN 429C (3.9 × 104conidia ml-1). The lowest LT50 was obtained at concentration of 108 and 107 conidia ml-1 for IRAN 429C (2.9 and 3.55 days, respectively). M. chamomilla essential oil had the lowest LC50 and LT50 values (19 µl l-1 air and 11.4 h), respectively. Longevity and population growth parameters, including the intrinsic rate of increase (rm), gross reproduction rate (GRR), net reproductive rate (R0), generation time (T) and finite rate of population increase (λ), were affected negatively by both agents. According to the results obtained in this study, both entomopathogenic fungi and essential oils could be used as an alternative to chemical insecticides in aphid IPM programs.

Esloveno. Bombaževa uš (Aphis gossypii Glover, 1877) je polifagna vrsta in je eden izmed najpomembnejših škodljivcev kumar v Iranu. V raziskavi so bili preučevani virulenca izolatov entomopatogene glive (Beauveria bassiana (Bals.-Criv-) Vuill.) IRAN 108, IRAN 429C and LRC 137 in insekticidna aktivnost dveh eteričnih olj ekstrahiranih iz vrst Matricaria chamomilla L. in Cuminum cyminum L. na odrasle osebke bombaževe uši v laboratorijskih razmerah. Podatki preživetja so bili analizirali glede na starost, spol in razvojne faze škodljivca. Podatki so pokazali, da so bili vsi izolati patogeni za uši, vendar se je virulenca med izolati razlikovala. Najmanjša izračunana vrednost LC50 je pripadala izolatu IRAN 429C (3,9 × 104konidijev ml-1). Najmanjša vrednost LT50 je bila dosežena pri koncentracijah 108 in 107 konidijev ml-1 za izolat IRAN 429C (2,9 in 3,55 dni). Eterično olje prave kamilice je imelo najmanjše vrednosti LC50 in LT50 (19 µl l-1 zraka in 11,4 h). Preživetje in parametri rasti populacije kot so potencialna rast populacije (rm), bruto reprodukcija (GRR), neto reprodukcija (R0), čas med dvema zaporednima generacijama (T) in končna velikost povečanja populacije (λ) so bili negativno prizadeti pri obeh obravnavanjih. Glede na rezultate pridobljene v tej raziskavi, bi kot alternativo kemičnim insekticidom v programih intergriranega upravljanja z listnimi ušmi lahko uporabili oboje, entomopatogene glive in eterična olja.