SHEDDING OF buttons in high numbers is a serious infestation of coconut. Deficient pollination due to low population of pollinating insects, unfavourable conditions such as drought and water logging, nutritional deficiencies and incidence of pests and diseases cause this problem.
Coconut is predominantly entomophilous, honeybees being the most important among the pollinating insects. If the reason for button shedding is deficient pollination, maintaining four honeybee colonies per hectare of coconut garden will help to overcome the problem. Substantial increase in fruit set can be achieved through this practice.
To ward off moisture stress, steps include mulching coconut basins with green/dry leaves at the close of monsoon, burial of coconut husk in circular trenches taken around the palm at a distance of 2m from the trunk, raising green manure crops and ploughing in for incorporation into soil to improve water holding capacity of soil and cover cropping with Pueraria phaseoloides and Calopogonium mucunoides as cover crops for coconut gardens. Water logging and consequent lack of aeration of soil may also cause button shedding. This problem is usually experienced in low-lying areas and can be overcome by improving drainage facilities.
Proper nutrition through application of manures and fertilizers is essential for maintaining health and productivity of palms. Organic manures are important as they supply nutrients as well as improve the physical properties of soil.
About 20-25 kg of organic manure along with the required quantity of inorganic fertilizers is the best combination for adult bearing palms.
Growing green manure crops in situ and their incorporation into soil is the easiest and most economic method of augmenting organic matter content of soil. Sunn hemp and cowpea are suitable green manure crops for coconut gardens.
Application of 0.5 kg of common salt along with 2 kg of wood ash per palm at the onset of southwest monsoon would give good result.
Button shedding due to pest and disease incidence can be effectively managed through suitable plant protection measures. Coreid bugs and their nymphs suck sap from buttons and tender nuts.
Infested buttons become deformed with characteristic crevices on the husk below the perianth and may fall or develop into crinkled/barren nuts. For the control of the pest apply 0.1 per cent Carbaryl on the inflorescences at early button stage after pollination is over.
Collection and destruction of fallen buttons and application of 2 per cent neem oil and garlic emulsion or micronised wettable sulphur 0.4 per cent on young bunches three times a year are recommended for the management of coconut eriophyid mite.
Shedding of female flowers and immature buttons are the common symptoms of `Mahali' disease caused by the fungus, Phytophthora palmivora.
Recommended control measure is spraying 1 per cent Bordeaux mixture or copper oxychloride preparation on the crown of palms, once before the monsoon and twice later at intervals of 40 days.
Sunny K. Oommen
College of Agriculture