PhilRice project 1.3 'Enhancing partnership with farmers in developing pest management in ampalaya rice-based farming systems in Southern Tagalog' [Philippines]

Pest and beneficial arthropods in ampalaya folds. Insect pests observed were melon fruit fly, Bactrocera cucurbitae, melon worm Diaphania indica, black bean aphid Aphis craccivora, cotton aphid Aphis gossypii and cutworm Spodoptera litura. The earliest that B. cucumbitae appeared in the field was at fruit setting. Diaphania indica fed on the ampalaya leaves and shoots and shifted to ampalaya fruit during the reproductive stage of the crop. The population level of D. indica was never high but damage can be substantial when it fed on the fruit. The presence of its larval parasitoid, Cotesia sp. can be a regulatory factor to its population. Other natural enemies found were spiders and coccinellid beetle Menochilus sp. Development/evaluation of non-chemical control tactics against ampalaya pests. The PhilRice Fiberglass Net Bag was introduced to the ampalaya farmers of Quezon, Laguna and Cavite through participatory or supervised field experiments. Results showed that when bagging, the sewed seams should be inside to give more volume to the bag and prevent fruit from coming in contact with the bag and consequently with the fruit fly oviposition and the best time to bag fruits was in the afternoon of the day when anthers and petals were dry. Delaying the bagging process will give more chance for fruit flies to lay their eggs on the exposed fruit. In several trials, bagging is as good as insecticide spray in protecting ampalaya fruits from fruit fly and melon worm damage. Farmers, however, are not enthusiastic to use net bag because bagging is more laborious than spraying. It takes 30 seconds to bag 1 ampalaya fruit. An information campaign about the benefits of bagging has to be intensified by PhilRice extension group. The biological control component focused on the development of mass rearing protocol for the melon worm parasitoid Cotesia sp. and evaluation of the feeding efficiency of general predator, earwig Euborellia annulata against larval instars of melon worms. Results showed that the female earwigs were more voracious than the males regardless of prey instar and that as the prey density increased, the prey consumption also increased. Meanwhile, Cotesia sp. was successfully mass reared in the laboratory using larvae of melon worm reared on fresh luffa leaves. In 1 year, a total of 12,727 Cotesia sp. pupae were easily produced using the protocol. Of these, 62% or 7883 emerged as adult parasitoids. Another experiment showed that Cotesia sp. only parasitizes 1st and 2nd instar D. indica and that the 1st instar larvae are more preferred by Cotesia sp. than the 2nd instar larvae for oviposition. Fruit fly pheromone bait (Amulet Cue Lure, BASF) was found effective in attracting wild male fruit flies up to a month. Weekly trap catches revealed that aside from B. cucurbitae, this pheremone trap also attracts B. dorsalis, B. umbrosa and B. philippinensis. The number of B. cucurbitae population. Toxicity of insecticides used by ampalaya farmers against melon worm. Insecticides are still the number one control tactic of ampalaya farmers even though not a single one is registered for ampalaya against melon worm. Five insecticides (based on survey of farmer usage in 2008) were evaluated against Diaphania indica in the laboratory. None of the insecticides tested caused 100% mortality 24 hours after dipping the larvae into the solution diluted at recommended rate. Cartap hydrochloride and methomyl caused 96% and 74% mortality of the 3rd instar of D. indica larvae, respectively. Other insecticides tested were labda cyhalothrin, cypermethrin and the mixture of chlorpyrites and BPMC. The results of these assays indicate that farmers, more often that not, are using chemicals that are not effective against melon worm because these were not evaluated and were not recommended against the insect. Actually, this practice may be considered misuse and has to be addressed by the regulatory agency and LGUs. Likewise, it may be imperative now for FPA to start the program of reregistration of old insecticides to eliminate those that are no longer effective against a given target pest. IPM Field Trials. On-farm sites in Cavite and Laguna were used to showcase the fiberglass net bags and fruit fly pheromone bait and VAM to ampalaya farmers as against their chemical control method. Results showed that bagging and spraying provided equal protection against melon fruit fly infestation. Yield from both treatments were not significantly different. The Laguna farmer was amenable to implement bagging of fruits instead of spraying. This farmer manages several hectares of rice fields with a core of farm workers to handle the day to day activities. On the other hand, Cavite farmer is reluctant to implement bagging, claiming that he does not have the time to bag all the ampalaya fruits in 800 sq.m. field, since he works alone and has to hire farm hand whenever he brings his produce and those of his neighbors in Tagaytay or Balintawak as a trader for additional income. Perhaps, the economy of scale operates in their decision. A supervised field trial involving combination of different IPM tactics showed that application of carbafuran 3g at transplanting, need-based spraying of insecticides during vegetative stage, releasing of Euborellia annulipes at 28 and 65 DAT, bagging of ampalaya fruits and use of plastic mulch, and use of microbial inoculants resulted in significantly higher yield than the other combination tested. The package need to be evaluated further and an economic analysis done.