Performance of aphid, Aphis craccivora on different host plants
Keywords:Aphis craccivora Koch., performance, nymphal mortality, fecundity, host preference, morphometrics etc.
AbstractPerformance of Aphis craccivora Koch (Aphididae; Hemiptera) on different host plants viz., cowpea,Â groundnut, cotton, sunflower, green gram and black gram was studied under laboratory conditions ofÂ 28Â±2Â°C temperature and 75-80% RH at S.V. Agricultural College, Tirupati, Andhra Pradesh. The totalÂ life cycle of A. craccivora was longest (336.0 Â± 37.9 hr) on cowpea and shortest on cotton (92.4 Â± 9.8 hr).Â Morphometrical data showed that aphids reared on cowpea were much bigger and gave birth to moreÂ number of young ones (52.0 Â± 10.9), followed by groundnut (21.1 Â± 2.6), green gram (12.6 Â± 8.3) and blackÂ gram (9.8 Â± 8.6). Highest nymphal mortality and zero fecundity of aphids reared on cotton and sunflowerÂ have given the status of least preferred host for growth, development and multiplication of aphids. TheÂ ranking of different host plants in terms of their preference (from most preferred to least preferred) forÂ growth, development and multiplication of A. craccivora were in the order of cowpea > green gram > blackÂ gram > groundnut > sunflower > cotton. Studies on host plantâ€™s physical characters revealed that trichomeÂ densities present on leaves of different host plants were negatively correlated with aphidâ€™s performance inÂ terms of adult longevity, fecundity and total life span; and positively correlated with percentage nymphalÂ mortality of A. craccivora. Biochemical analysis of different host plants, showed that protein content ofÂ different host plants had a significant negative impact on the total nymphal duration of A. craccivoraÂ however they had a positive correlation with the fecundity of A. craccivora. Phenol content of host plantsÂ was significantly negatively correlated with aphidâ€™s performance in terms of biological parameters suchÂ as total nymphal duration, adult longevity, fecundity and total life span; phenols also had a significantÂ positive correlation with nymphal mortality. Free amino acids had a high degree of positive correlationÂ with aphidâ€™s biological parameters such as adult longevity, fecundity and total life span. Reducing sugarsÂ were negatively correlated with nymphal durations, fecundity, adult longevity and total life span of A.Â craccivora.
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