CONTROL OF COCOA POD BORER AND PHYTOPHTHORA POD ROT USING DEGRADABLE PLASTIC POD SLEEVES AND A NEMATODE, Steinernema carpocapsae

摘要

Cocoa pod borer (CPB; Conopomorpha cramerella) and Phytophthoraudpod rot (PPR; Phytophthora palmivora) are seriousudpest and disease on cocoa plantations in Indonesia. Both pestudand disease have been controlled with limited success usingudcultural practices such as pruning, frequent harvesting, sanitation,udplastic sleeving, and chemical pesticides. An experimentudwas conducted on cocoa plantings in Pinrang Regency, SouthudSulawesi during the wet season of 2008/09 to test the effect ofudpod sleeving (with transparent degradable and non-degradableudplastic bags) and nematode application on CPB and PPR infestation.udThe nematode, Steinernema carpocapsae (10,000 activeudjuveniles per pod) was sprayed three times at intervals of 10 andud20 days. Pod damage by CPB was observed at harvest time, whileudPPR disease incidence was evaluated every week until harvestudtime. Results showed that all pods in the field were infested byudCPB as indicated in control samples. Pod sleeving using bothudnon-degradable and degradable plastics significantly reduced poduddamage by CPB, from 62.3% in the control treatment comparedudto 8.4% in the CPB treatment. A combination of pod sleevingudand nematode application had a synergistic reduction of poduddamage by CPB resulting in totally healthy pods. Pod sleevingudwith degradable and non-degradable plastics also reduced poduddamage by PPR significantly. Pod sleeving with non-degradableudplastic suppressed the disease incidence almost zero until 6 weeksudafter sleeving and the rate of disease incidence was 3.6% perudweek. However, with degradable plastic, the disease suppressionudwas even longer (7 weeks after sleeving), indicating that theuddegradable plastic is more effective. Combination of sleeving andudnematode application slightly increased PPR infection. Sleevedudpods in general had lower rates of PPR infection compared toudpods treated with nematode or untreated pods (control). In theseudtwo applications, the rate of disease incidence was 7.8% andud8.3% per week respectively. The study implies that biologicaludcontrol using entomopathogenic S. carpocapsae and degradableudplastic sleeves are effective and environmentally-friendly toudcontrol C. cramerella and P. palmivora on cocoa.ud[Keywords: Theobroma cacao, Conopomorpha cramerella,udSteinernema carpocapsae, Phytophthora palmivora, pest control,