- The bugs and their nymphs feed from the inflorescence, young nuts and tender coconut by piercing and sucking the juice.
- The damage to nuts varies depending upon the point at which the insect pierces for feeding.
- If the feeding point is just below the perianth such nuts fall down in due course.
- During feeding, the bug injects a toxin due to which the cells of the nut get damaged resulting in nut fall.
- When such fallen nut is examined after removing the perianth development of cracks can be seen due to feeding injury.
- If the feeding point is just below the perianth such nuts do not fall and develop in to mature nuts and in such cases the developing nuts remain crinkled.
- These damaged areas exhibit furrows with gummosis.
- The damaged nuts which are retained on the tree will develop in to under sized or barren nuts.
- The husk of the crinkled nuts become hardened and cause difficulty in dehusking.
- The copra content is also reduced which in turn affects the market value. If the attack is severe the % of barren nuts will increase.
The population of coreid bugs start during June and reaches its peak during September-October and then decline.Select 20 trees at random from a plot and collect the fallen nuts and look for the symptoms of damage after removing the perianth. Record the average damaged nuts per tree. Less than 5 damaged nut : mild, 5-10 moderate and > 10 severe.
10 damaged nuts.
- Chrysochacissa oviceps (Torymidae) and Grayon homoeceri (Scelionidae) are egg parasites of the bugs.
- Guava, neem, cocoa are alternate hosts of the pests, hence measures adopted to control pests in coconut palms should also be carried out on the alternate hosts.
- Apply 0.1% carbaryl 50 WP or quinalphos 25 EC 0.05% on the entire crown, excluding the newly opened inflorescence, the leaves and old bunches.
- Spraying may be carried out three times in a year during the beginning of June, September-October and also during November on need base.
- Spraying insecticides should be done during evening to avoid disturbances to honey bees.