Infestation induced biochemical reactions on papaya by mealybug, Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae)

Abstract

Paracoccus marginatus Williams and Granara de Willink, (Hemiptera: Pseudococcidae) is an invasive alien sucking pest that attacks several genera of economically important tropical and subtropical plants. Biochemical study revealed that total protein content was very low (1.88mg/g) in plants inoculated with third instar nymphs of papaya mealybug, whereas the plants inoculated with adult mealybugs recorded a higher protein concentration of 4.60 mg/g. Similarly, plants inoculated with third instar nymph of papaya mealybug had a decreased mean concentration (0.019 mg/g) of Indole Acetic Acid (IAA) whereas plant inoculated with adult mealybugs recorded the highest mean IAA concentration was 0.070 mg/g. The papaya seedlings uninfested with papaya mealybug recorded the highest protein (5.34 mg/g) and IAA (0.185Â mg/g) content. However, the gibberellic acid content of 5mcg/g was estimated from the leaves of plants showing crinkling symptom infested with third instar nymphs and the uninfested papaya seedlings recorded lower levels of gibberellic acid content of 1 mcg/g.