การศึกษาศักยภาพของเชื้อราก่อโรค Aschersonia spp. เพื่อการควบคุมแมลงหวี่ขาวส้ม Dialeurodes citri (Asmead) (Hemiptera: Aleyrodidae)

Abstract

Aschersonia spp. is entomopathogenic fungi which specific for controlling whiteflies and scale insects. Dialeurodes citri (Hemiptera: Aleyrodidae) is an economically important insect pest of citrus. The objectives of research were studied morphological characteristics of citrus whitefly, D. citri and Aschersonia spp., population dynamics of citrus whitefly, D. citri in lime orchard, Phrom Khiri district, Nakhon Si Thammarat province, for a year during June 2016 to May 2017 (there were obtained 3 lime orchards A, B and C)., potential of entomopathogenic fungi, Aschersonia spp. for controlling citrus whitefly, D. citri in lime orchard and whitefly, B. tabaci in laboratory. The results revealed that the morphological characteristics identification of Aschersonia spp. were 3 species; Aschersonia placenta, Aschersonia samoensis and Hypocrealla raciborskii. The population of citrus whitefly, D. citri nymphs were the highest level in lime orchard A in July of 49.97 +45.40 nymphs per leaf and were high beneath the old leaves of 30.79+33.20 nymphs per leaf. Percentage infected of Aschersonia placenta peaked in lime orchard B in May of 81.10 percentage and beneath the young leaves of 25.63 percentage. A study of pathogenicity of A. placenta and A. samoensis showed that citrus whitefly, D. citri were infected with spore concentration at 1×10 spore/mL for 21 days. The infected percentages of A. placenta and A. samoensis were 59.51 and 14.96 percentage, respectively. In conclusion, A. placenta has a potential use for controlling citrus whitefly, D. citri in lime orchard and whitefly B. tabaci in laboratory experiments.