The Efficacy of pesticides against spider mites (Tetranychus urticae koch) on chrysanthemum (Chrysanthemum morifolium ramatuelle)

Abstract

Chrysanthemum cut flower production is one of the sources of income of many local farmers in the cool regions of the country. The problem lies in the significant drop of production due to spider mite damage. These mites are difficult to control due to their rapid reproduction and their own protection and their protection underneath webs on the lower surfaces of leaves. Since these plants are reared for their aesthetic value, prompt and thorough protection is needed. The most practical means of control is the use of pesticide sprays. This study aimed to evaluate the efficacy of these pesticides on mites, which will serve as a guide for local farmers. The study aimed to find out the best pesticide against spider mites on Chrysanthemum morifolium. The subproblems are: (1) Is there a significant effect of the five pesticides namely Dicarzol, Vydate, Tedion, Kelthane and Karate against spider mites on Chrysanthemum morifolium? (2) Is there a significant difference in the effect of the five pesticides namely Dicarzol, Vydate, Tedion, Kelthane and Karate against spider mites on Chrysanthemum morifolium? (3) Is there a significant difference in the effect of the five pesticides against spider mites on Chrysanthemum morifolium varieties Taiwan yellow, Bangkok yellow and Spider white? (4) Is there a significant interaction and effect of the variety of the chrysanthemum and the pesticide against spider mites? This study made use of the experimental method of research using split plot in completely random design (CRD). The experiment started on October 21, 1991 and lasted until December 5, 1991 at the Baguio National Crop Research and Development Center, Baguio City, The data gathered were mite count a day before and after application of the pesticides for three-week, two-week and one-week intervals. The analysis of variance for split plot in completely random design was used to test the variety treatments, the Duncan’s Multiple Range Test (DMRT) was used to find out which among the treatments differed significantly from each other. There was a highly significant effect of the pesticides against spider miters on chrysanthemum morifolium. There was a significant difference in the effect of the five pesticides against spider mites on Chrysanthemum morifolium. However, Kelthane, Karate and Dicarzol did not differ significantly in their effect in the control of mite population. There was no significant difference in the effect of the pesticides against spider mites on varieties Taiwan yellow, Bangkok yellow, and spider white. There was no significant interaction effect of the variety of the chrysanthemum and the pesticide against spider mites. The use of the pesticides against spider mites sharply reduces the mite population on chrysanthemum plants below the untreated check. The efficacy of the pesticides against spider mites are significantly different from each other. Kelthane held a great potential in the control of mites. Dizcarzol and Karate were also as effective. Tedion was not so effective but has been found to have low toxicity to mammals. The variety of the chrysanthemum morifolium did not affect the efficacy of the pesticides against spider mites. Kelthance, a German product, should be introduced to local manufacturers in the Philippines for easy access to local farmers. Spraying at every two week interval is recommended until flowers emerge. The use of pesticides against spider mites is recommended until biological control is introduced. Students and researchers in the field should make follow-up research using another period of the year especially during the hot months. Similar researchers on other crops could also be done.