A detailed statistical analysis of a balanced, incomplete block experiment with insecticides to control tomato spotted wilt is given. The effect of the treatments was studied in relation to stand an yield. The angular transformation was used for stand, and the analysis of stand and yield was made with and without the inter-block information. The results indicated that all insecticides tested, viz. Rhodiatox, Fosfern, Hexason 2510 M, Toxaphene, and tartar emetic reduced the number of plants killed by spotted wilt. The higher the concentration of the insecticides the better was the gain in stand. Some insecticides had a detrimental effect on the plant, at, high concentrations. In relation to yield the treatments could be placed in two groups : a) a group in which ilemage caused by the treatment was greater than the benefit, resulting from a better stand with no gain in yield ; b) a group in which there was also a gain in yield.