Indian Agricultural Research Institute, New Delhi-12
Blood Red, Mosambi and Washington Navel sweet orange trees were treated with 0.5 per cent ZnSO4, 1 per cent urea and DBCP separately and in combinations with a view to evaluate their effects on chlorosis, shoot growth, nematode population, yield and quality of fruits during 1968 and 1969. The studies revealed that the percentage chlorosis was significantly lower and extension shoot growth was significantly increased in trees sprayed with zinc singly or in combination with urea and DBCP as compared to trees treated with DBCP or urea or control. Tylenchulus semipenetrans was observed to be highest in number among the total nematode population. In these studies the nematode did not play any important role in the chlorosis of sweet orange trees. Zinc treatments improved the average yield as number, weight and diameter of fruits over control. In general, there was no significant difference in average yield in trees treated with urea, DBCP when compared to control. The difference in juice contents, total soluble solids and total acidity were considered relatively small among various treatments.
