000			04918nam a22002177a 4500
999			_c291397 _d291397
082			_a632.6 _bFAS/BI PG
100			_aFasna Sherin, K
245			_aBioefficacy of entomopathogenic fungi against cassava mealybug, phenacoccus manihotti matile-ferrero (Hemiptera: Pseudococcidae)
260			_aVellanikkara _bDepartment of Agricultural Entomology, College of Agriculture _c2024
300			_a82,xixp.
502			_aMSc
520	3		_aCassava mealybug (CMB), Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae) is a major insect pest of cassava. It causes severe damage by stunting the growth points of cassava plants, sometimes totally defoliating the plants. Level of infestation and yield loss by cassava mealybug varied from 30 to100 and 30 to 90 per cent respectively. In India, the occurrence of this pest was first noticed on cassava in Thrissur, Kerala during April 2020. Control of mealybugs commonly relies on the use of insecticides. But, it is difficult to control mealybugs using insecticides, due to their cryptic life cycle, presence of waxy coating, and formation of dense colonies. Management of insect pests using entomopathogens has received considerable importance in recent times. As part of AICRP programme of 2020-22, AICRP on BCCP, Thrissur centre conducted survey in cassava growing fields of Thrissur and Palakkad district to assess the species composition of mealybugs, damage intensity and associated natural enemies. During the survey, mycosed cadavers were collected and seven isolates of entomopathogenic fungi were obtained. Out of seven, five entomopathogenic fungal isolates were selected, characterized and evaluated under the present study entitled “Bioefficacy of entomopathogenic fungi against cassava mealybug, Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae)”. The identity of five isolates was confirmed through morphological, cultural and molecular characterization. The fungal isolates were identified as two isolates of Simplicillium aogashimaense (EPF 2 and EPF 4), two isolates of Purpureocillium lilacinum (EPF 3 and EPF 7) and one isolate of Lecanicillium psallioate (EPF 5). Pathogenicity of these fungal isolates was tested against second instar nymphs of cassava mealybug, P. manihoti in the laboratory. A preliminary screening bioassay was carried out initially, and the superior isolates were subjected to dose-response and exposure-time response bioassay. In the preliminary screening bioassay, P. lilacinum isolates (EPF 7 and EPF 3) recorded more than 90.0 per cent mortality. S. aogashimaense (EPF 4) and L. psalliotae (EPF 5) registered mean mortality of 82.5 and 75.0 per cent respectively. S. aogashimaense (EPF 2) recorded the lowest mortality of 70.0 per cent, which was significantly lower than all other isolates. The best four isolates in the pre-screening were subjected to dose-response and exposure time- response bioassay. Spore suspensions of five different concentrations ranging from109 to 105 spores ml-1 were tested against mealybug. Ten days after treatment, two isolates of P. lilacinum (EPF 7 and EPF 3) recorded more than 80.0 per cent reduction in population of mealybug at the concentration of 109 spores ml-1 . The same isolates showed low LC50 and LT50 values. Efficacy of these two superior isolates of P. lilacinum (EPF 7 and EPF 3) at concentration of 1×108 spores ml-1 was evaluated in a pot culture experiment. The isolates were compared with a standard biocontrol check, NBAIR isolate of Lecanicillium lecanii @ 1×108 spores ml-1 , a botanical insecticide (neem oil emulsion @ 2%) and a chemical insecticide, dimethoate 30 EC @ 1.5 ml L-1 . Maximum reduction in the mealybug population was observed in dimethoate treated plants (99.86%). Even though, the neem oil emulsion (2%) showed significant effect on mealybugs, certain signs of phytotoxicity were observed in treated plants. Among three fungal isolates, significantly higher reduction in population was observed in P. lilacinum, EPF 7 (78.55%) followed by P. lilacinum, EPF 3 (74.92%), and both being on par with each other. In conclusion, the present study revealed that biological control of cassava mealybug, P. manihoti using two promising isolates of P. lilacinum could be a viable component in the integrated pest management. Two rounds of foliar application of any of the two isolates of P. lilacinum (EPF 3 and EPF 7), at 15 days interval at the dosage of 1×108 spores ml-1 was found effective against cassava mealybug, P. manihoti.
650			_aAgricultural Entomology
650			_aCassava
650			_aEntomopathogenic fungi
650			_aPhenacoccus manihotti
650			_aHemiptera: Pseudococcidae
700			_aSmitha Ravi (Guide)
856			_uhttps://krishikosh.egranth.ac.in/handle/1/5810220084
942			_2ddc _cTH