Management of eggplant and shoot borer, Leucinodes orbonalis Gueene (Lepidoptera: Pyralidae) and other major insect pests of organically grown eggplant with emphasis on biological control agents and botanical insecticides in Quezon, Laguna and Batangas [Philippines]

The effectiveness of different component non-chemical control methods (mulching release of earwigs, spraying of langkuas + oregano crude water extracts, planting of lemon grass as repellent and sanitation) that were previously reported to be effective against eggplant fruit and shoot borer (EPSB) was determined in two consecutive trials in the Central Experiment Station, UPLB [University of the Philippines Los Baños] from February to June 2015. The effectiveness of the non-chemical control methods was compared with the spraying of methomyl, the conventional method of controlling EPSB. On the other hand, the release of earwigs in combination with the release of Trichogramma chilonsis against EPSB was conducted in San Pablo City (SPC), Laguna [Philippines]. Each component control method that was found effective against eggplant fruit and shoot borer (EFSB) in year the author was investigated and integrated and evaluated in two experiments in an organic farm in Brgy. [village] Bautista, San Pablo City (October 2015 to February 2016 and June to October 2016). In Experiment 1, the following treatments were evaluated: integration of rice straw mulching + earwig + Trichogramma (T1); rice staw mulching + earwig + Trichogramma + botanical insecticide (T2); rice straw mulching + earwig + Trichogramma + botanical insecticide + sanitation (T3); and rice straw mulching+ release of Trichogramma (T4). The EFSB fruit damage in the different treatments ranged from 41.61 to 48.49% while marketable yield ranged from 3.19 - 3.84 tons/ha which do not significantly differ among treatments and the control. This suggests that the integration of the different control methods is not sufficient to reduce EFSB damage. In Experiment 2, the following treatments were evaluated: rice straw mulching + earwig (20,000) earwigs/release/ha) (T1); rice straw mulching + earwig (40,000 earwigs/release/ha) (T2); rice straw mulching + botanical insecticide (T3); rice straw mulching + earwig (20,000 earwigs/release/ha) + botanical insecticide + sanitation (T5); and Control (T6). The EFSB damage in all treatments was very high (63.40 - 68.79%) and does not significantly differ among treatments (8.70-11.40 tons/ha) and the control, more than 20% increase in marketable yield was obtained in rice straw mulching + earwig (20,000 earwigs/release/ha) + botanical insecticide + sanitation (T5) followed by rice straw mulching + earwig (20,000 earwigs/release/ha) (T1). Observations in the Experiment 2, showed that plants sprayed with neem leaf extracts had a very low insect infestation and reduced. Therefore, the effectiveness of neem in combination with langkuas was verified in the field in Brgy. Bautista, San Pablo City, Brgy. Santissima, Sta. Cruz, Laguna, Brgy. Behia, Tiaong Quezon and Brgy. Bocohan, Lucena City. Among the Trials conducted, the highest net income was obtained in Trials 1 and 2 (SPC) followed by Trial 5 (Sta. Cruz). The highest Return of Investment (ROI) of 423.90% was obtained in Trial 5 followed by Trial 6 (Lucena City) of 365.74% (Table 43). The lower marketable yield in Trial 6 as compared to other Trials was due to the limited number of harvesting. Trials 1 and 2 was harvested 20 times. Trial 3 and 4 was harvested 14 times, Trial 5 was harvested 12 times while Trial 6 was harvested only 8 times. Results of Trials 1 to 6, suggested that the implementation of the OPM technology (integration of the field releases of earwig + mulching, regular removal of infested shoots and fruits, and the spraying of the 1:1 langkuas - neem crude extract combinations) provided an average of 24.52% EFSB infestation by and 46.84% reduction in EFSB damage compared with FP of controlling the pest. Meanwhile, the weekly spraying of OPM technology provided 13.36% EFSB infestation while 15.75% for FP. The OPM technology provided an average of 50% increment in marketable yield and about 65% increase in net income in comparisons with the untreated plants and FP of controlling the insect pests of eggplant.