*4.1.2.2 Management*


*Integrated Pest Management (IPM) in Oil Palm,* Elaeis guineensis *Jacq. DOI: http://dx.doi.org/10.5772/intechopen.108580*


#### *4.1.3 Bag worm,* Metisa plana *(Psychidae)*

Bag worm, *Metista plana* is observed in moderate levels with quite six case worms per leaflet in Andhra Pradesh state all the year round. However in Karnataka the incidence is heavy during the monsoon and winter months. Cocoa (*Theobroma cacao*), coconut (*Cocos nucifera*), edible seed (*Areca catechu*) and areca palm (*Dypsis lutescens*) are observed as collateral hosts for the pest. There are nine different species of caseworms known to infest oil palm in India. *Metisa plana*, *Manatha albipes*, and *Crematopsyche pendula* were the most often seen species. In almost all the gardens, the pest is observed endemic with the presence of all the stages at any date of observation. Psychid incidence is observed during of July to March leaving the summer months with a percent incidence varying 0.39–8.8 in several palms. Young gardens of but 5 years recorded less incidence compared to middle aged ones. The fundamental cause of the higher prevalence compared to young gardens where such conditions are absent is the observed overlapping and intermixing of leaves of neighbouring palms, which prevents sunlight from penetrating into the older gardens. Unfavourable abiotic conditions, such as high temperatures during the pre-monsoon period, a delay in the monsoon, and heavy rains throughout the monsoon season, may be linked to the natural death of psychids that was seen over the summer and rainy period. Although the pest maintains congenial conditions suited to its growth and development within the bag by regulating the desired temperature and humidity, during this time of year it could not maintain dryness and through hot summers, it's unable to take care of the specified humidity resulting in mortality of the pest (**Figure 4**).

#### *4.1.3.1 Biology and nature of harm*

The pupal cocoons, which are hidden in sacks, contain 60–80 eggs laid by wingless female adults. The fecundity can occasionally be quite high. The egg cycle lasts 16 days. Before pupating, the larva typically needs 100–125 days. Just five larval instars are seen in males and seven instars in the case of females. The larvae and adults possess black pectinate antennae. Because the caterpillars mature, they turn within the bag, changing from a feeding position with their heads oriented toward the plant surface. It takes 26 days to reach the pupal stage. The primary instar larvae after hatching from eggs are naked with no bag. They start feeding on the mother's bag as soon as they hatch, eventually forming their own bag. Caterpillars live in a case while they are developing. Each species' case/bag has a specific form and outward

**Figure 4.** *Psychids feeding on oil palm.*

appearance. The pupae are found within the luggage and are just plain cocoons. The males have wings and are able to fly.

The abaxial surfaces of the fronds are scarified by caterpillars in their early stages. The full leaf tissue is chewed by caterpillars in later instars, which also create holes and notches in the leaf tissue by feeding at the leaf margins. When bagworms feed, the surface develops holes and grooves as well as dry necrotic areas where the surface has been destroyed. Bagworms attack the center and older fronds of the palms, with younger fronds usually remaining free from damage. Damage by psychids is severe only the population is incredibly high. The yield of the palm suffers from gradual necrosis and ultimately skeletonization. Defoliation by the bug results in a loss of 3.88% of each palm's photosynthetic area.
