Volume 19, Issue 5
May 1944, pages 147-187
pp 147-151 May 1944
Pan diseases have been found to be a serious menace in the district of Sylhet. They were first reported in 1929.
A careful survey has revealed that due to thepan diseases the area underpan in the district has decreased from 1,513 · 8 to 679 · 8 acres; the number of families growingpan has decreased from 4,709 to 3,348; the life of aboroj has decreased from 15–30 years to 3–5 years and the yearly monetary loss due to the death of the plants comes to Rs. 8,49,748!
The diseases ofpan according to their relative importance have been found to be thePhytophthora foot-rot and leaf-rot, theRhizoctonia root-rot, theSclerotial wilt and aGloesporium leaf spot.
pp 152-164 May 1944
pp 165-170 May 1944
As a result of the experiments conducted with different manures it was found that the percentage of death ofpan plants due to the attack ofP. parasitica is not influenced by the nature of the fertilizing material. The percentage of death has been found to be practically the same in the plots receiving oil-cake, sodium nitrate, ammonium sulphate singly or sodium nitrate or ammonium sulphate in combinations with superphosphate and potassium sulphate. The yield of leaves, however, has been found slightly more in the oil-cake treated plots.
pp 171-175 May 1944
pp 176-187 May 1944
The life-history and bionomics ofPhthorimœa operculella Zeil. has been studied under Poona conditions. Effect of various volatile substances has been worked out. Naphthalene has yielded very encouraging results in so far as oviposition may be reduced by about 43 · 3% if the pupœ are exposed to its vapour for about 66 hours. The eggs do not hatch at all and the adults which emerge under these conditions die soon after without laying. The infestation even when present in the tubers does not develop further. The effect is equally beneficial in airtight and ventilated conditions. Other substances have not yielded very encouraging reasults.