Abstract
Purpose: Cryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae) is a well-known biocontrol agent that is widely used to control soft-bodied insects including papaya mealybug. This study aimed to evaluate the behaviour of C. montrouzieri to chemical simulants associated with honeydew (HD) and crushed papaya mealybugs (CPMBs), under laboratory conditions.Research Method: The larvae and adult stages of C. montrouzieri were introduced into a Petri dish containing HD or CPMBs treated and untreated Carica papaya (Papaya) leaf discs, and the behaviour was recorded for 20 minutes using video surveillance. Searching time, walking speed, and number of turns on leaf discs were quantified. Findings: Results revealed that the searching time of C. montrouzieri, on papaya leaf discs was significantly varied with different larval instars and adults (F(4,298) = 17.21, p<0.05) as well as leaf-coated substances (F(2,298) = 78.07, p<0.05). When considering all larval instars of C. montrouzieri searching time on CPMBs (690.7 ± 25.3 s) was significantly higher compared to HD (524.8 ± 33.5 s) and clean leaf disc (219.6 ± 34.4 s) (F(2, 227) = 60.61, p<0.05). The searching period of the first larva (L1) was significantly higher compared to adults in all treatments (p<0.05). The walking speed of the fourth larva (L4) and adults of C. montrouzieri on HD and CPMBs leaf discs was significantly lower compared to that of clean leaf discs. The number of turns per unit path length was significantly higher in both HD (1.100 /cm) and CPMBs (1.129 /cm) leaf discs compared to the control (0.501 /cm) concerning larvae and adults.Originality/value: It leads to the conclusion that HD and CPMBs considerably change the searching behaviour of larvae and adults of C. montrouzieri. Further work should be focused on examining and utilizing these chemical cues for searching to enhance the efficacy of C. montrouzieri in controlling papaya mealybug.
Publisher
Sri Lanka Journals Online