Philippines IPM project 03: Ecology and management of agromizid leafminers in onions.

Duration: Five (05) years  (2001-2006)

Purpose: To augment paucity of knowledge on agromyzid leafminers infesting onions and to address the development of management or control strategies for the agromyzid leafminer pest(s) of onion

Background/description: Onion is prominent culinary vegetable of the world. In the Philippines, onion is a rice-based key commodity particularly in the provinces of Ilocos, Nueva Ecija, Pangasinana, Nueva Vizcaya and Occidental Mindoro. Incidence of insect pests in onion is not uncommon in view of the extensive cropping of onion during its growing season (November to April). The major pests of onion during its growth are thrips and cutworms. The use of pesticides for insect pest control has been a popular and regular practice of farmers to alleviate the infestation of these pests. However, studies have shown that pesticide misuse is a common practice and can over long term lead among others to the reduction of natural enemies, development of resistance etc. In the case of onions and beans, the control with chemical pesticides has developed resistance to about 449 species of insects and mites due to either increased or decreased dosage and frequency of application. Many also researchers emphasized that leafminers are notoriously difficult to control with the use of insecticides alone as they are resistant to many of the conventional insecticides. It was further suggested that to control the larval stages of agromyzid leafminers, insecticides must possess systemic and translaminar properties. Among the factors that led to the elevation of leafminers from potential to major pest were collated as follows: (1) Failure of quarantine procedures, (2) Use of pesticides without regard to development of resistance, (3) Extreme polyphagy of leafminers, and (4) Lack of knowledge of farmers on alternative control measures. Studies of the project include: (a) Determination of yield loss, (b) Survey of onion farmers, (c) Biological studies and host ranges, (d) Determination of leafminer species of onions.

Agro-ecological Zone(s) and locations: Ilocos Sur and Ilocos Norte, Nueva Ecija, Pangasinan, Nueva Vizcaya and Occidental Mindoro (the six top provinces for onion production)

Expected Outputs: 1) Generate database information on agromyzid leafminer of onions, 2) Determine yield loss, life histories and host, 3) Develop management strategies for leafminers of onions that will jive with management practices for more known pests.

Potential impact and beneficiaries: Onion farmers are the primary beneficiaries of the results, as well as the onion consumers as a whole

Partners:  a) Department of Agriculture-Bureau of Agricultural Research (DA_BAR)

Contact person(s)/principal investigator(s): Elaida R. Fiegalan (project leader), ilyxyz229@yahoo.com and Marita D. Salinas-Labe (study leader for biological studies