Yield and drupe characteristics of coconut palms affected with Leaf Scorch Decline

The yield and drop characteristics of healthy coconut palms have been compared with those of palms affected by leaf Scorch Decline wich have been grouped into Mild Leaf Scorch Decline, Moderate Leaf Scorch Decline and Advanced Leaf Scorch Decline. Significant reduction in yield and drupe componenets have been observed in palms showing moderate and advanced Leaf Scorch Decline while the difference in these characteristics between healthy palms and those showing mild Leaf Scorch Decline was not significan

Leaf blight disease of coconut 1.Studies on Pestalozzia palmarum

The cultural behaviour of Pestalozzia palmarum cooke was studied on different agar media. Temperature-growth studies indicated that the colony growth and sporulation of the fungus were best at 25°C. The fungus grew best on potato dextrose agar. The optimum temperature for the germination of conidia was 25°C. Germination was reduced with the increase of concentration of conidia. It is doubtful whether P. palmarum is the primary cause of leaf blight of coconut in view of its inability to readily infect healthy coconut leaves

Leaf blight disease of coconut 2. studies on Curvularia sp

The cultural behaviour of Curvularia lunata Wakker, which caused lesions in leaves of coconut seedlings, was studied on different agar media. Temperature -growth studies indicated that the colony growth and sporulation were best at 30 perc. The optimum temperature for germination of conidia on water agar was 30 perc. Germination was reduced with the increase of concentration of conidia, and was less on leaf surface than on water agar. When coconut leaves were inoculated with C. eragrostidis which was occasionally isolated from lesions, failed to produce any symptoms on inoculatio

Some studies on the biological control of chromolaena odorata (Eupatorium odoratum)

Laboratory studies on the biology and life cycle of the deforliator insect Ammalo insulata walk. (Lep. Arctiidae), introduce to Sri Lanka to control the pernicious weed Chromolaena odorata Robinson, indicated that the insect could complete the life cycle on the two known hosts, C. odorata and Ageratum conyzoides but preffered C. odorata Fluctuations on the deforliator insect population in a locality were monitored while periodc increases of the insect coinciding with new generations were noted. Larval and pupal mortality appear to be major constraint in the successful establishment of the insect. The larval population was also low during the dry season. Some changes inthe insect population in relation to host and climatic factors have been noted