Study identifies Dynamics of Jackfruit Infestation

With a recorded 18 commercial and non-commercial uses, jackfruit (Artocarpus heterophyllus lam. ) displays great export potential specially as the fruit is gaining increased popularity beyond Asian shores. The Department of Agriculture (DA) has made jackfruit one f its banner commodities, attesting to this fruit’s foreign earning generation capacity.

In Eastern Visayas, efforts are underway to commercialize this crop. But the full commercializiation of jackfruit, like other crops, encounter numerous problems which all result to low yields. Insect pest attack is the most predominant obstacle to the growth of the Industry in the said region. Jackfruit is considerably attacked by fruit fly (Bactrocera umbrosa Fabr.) during the fruiting period, according to Coronel (1979).
In any crop production scheme, crop protection is always crucial to prevent insect-pest infestations. Crop protection activities include: a0 pest indentification, b) population fluctuation, c) assessment of damaged done by the insect pests and d) understanding of some biological information of the insect pests ( life cycle, mortality, alternate host, and natural enemies attacking of insect pests.)

However, literature or information on insect infestation conditions, in Eastern Visayas in particular is not available.
A study was conducted in Eastern Visayas to identify the dynamics of insect pests associated with jack fruit. The study identified insects pests that attacked crop in provinces of Leyte, Southern Leyte, Samar, Northern Samar and Eastern Samar. It also determined the population fluctuation while developing an understanding of the bsic biological information, assessing the damage inflicted by the major insects pests and establishing a management system for the major insects pests.

Monthly surveys and sampling of the insect pests from the selected municipalites of teh above provinces revealed 10 insects pests that attack the crop – bark borer/stem borer, gray mealybug, pink waxy scale, cottony cushion mealybug, white grub, red worm, fruit fly , fruit borer and leaf weaver.

These pests are present throughout the year and infest the crop at various stages of growth and at various parts.

Fruit fly (bactrocera umbrosa) and pyraustid and curcullionid fruit borers were the most dominant in terms of number and damage inflicted. The insect feedings considerably destroyed the fruits of the crop.
The pyraustid and curcullionid fruit borers are newly identified insect pests. The overall metamorphosis and the natural controlling factors of these borers were determined under laboratory conditions. In the cages and glassware, the borers are capable of producing several generations given their total life cycle (33.8 days for pyraustid fruit borer and 65.8 days for curcullionid fruit borer). However , in the actual crops, their life cycles were higher, Mortality of the norers in its original hosts is higher during the first instar period of the larva and tends to decrease as the growth of the insect-pests progresses. Collected larvae from the filed showed parasitism by Apanteles sp.. a hymenopterous parasite.
The control of fruit fly and fruit borers attacking jackfruit was also studied. Five strategies of control against fruit fly on jackfruit were tested. The use of Dipterex (0.75 kg ai/ha applied at the fruit setting and bi-weekly therafter) and bagging the fruits earlier effectively reduced infestation.

Source: BAR TODAY July-September 2000. Mario A. Martinez and Rufino B. Ayaso,III

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