Cultivar resistance of safflower against some insect pests

Results regarding thrips infestation on different cultivars of safflower showed that the pest appeared on crop in the fourth week of January and remains up to first week of March 2004. There was a significant difference of population on different cultivars. The highest mean population of 1.82 insects per leaf was recorded on GS/25 PI-250077, while the lowest 1.18 was observed on cultivar GS/48 PI-405998. The pest population development on different dates was also significantly different. Correlation studies carried out between environmental factors and thrip population showed a significant negative correlation between maximum temperature and thrip population. Jassid started their infestation in safflower crop during the second week of January and continued till the second week of March 2004. The highest population of 0.80 insects per leaf was recorded on cultivar GS/ 11 PI-262419. The jassid population during different dates of observation was significantly different, correlation carried out between environmental factors and jassid population was not significant. The population development of white fly on different cultivars of safflower indicated that there was no significant effect of cultivars. However, it was found present in crop from second week of January to fourth week of March. The highest and lowest population of 1.33 and 0.99 insects per leaf was recorded on cultivars GS/22 PI-401479 and GS/39 PI-405974, respectively. There was significantly negative effect of temperature on the population development of white fly. The over all seasonal mean population of safflower aphid on different cultivars was significantly different from each other. The maximum and minimum population of aphid 0.91 and 0.71 was recorded on cultivar GS/19 PI-401476 and GS/43 PI-405988, respectively. The aphid population on different weeks of observations was significantly different there was no effect of environmental factors on population development of safflower aphid. The shoot fly population indicated that there was significant difference in population development of different cultivars of safflower. The maximum population of 0.80 shoot fly maggots per plant was observed on cultivar GS/1 PI-253894, whereas there were some cultivars, which had zero shoot fly infestation. The shoot fly population recorded on different weeks showed a significant difference. Temperature (maximum and average) had a significantly negative effect on population development of shoot fly, respectively. The results indicated that the infestation level of H. armigera on different safflower cultivars was low, moreover the population development of pest on different cultivars was not significantly different from each other. The maximum and minimum population of 0.76 larvae per plant was observed on cultivars GS/1 PI-253894; whereas no infestation was recorded on many cultivars. H. armigera population during different time intervals indicated that there was a significant effect of time intervals on population development. It is concluded that thrips, appeared on different safflower cultivars in fourth week of January and remain there up to first week of March. Jassid and shoot fly started during second week of January and continued till the second week March. The white fly found presents from second week of January and remains there up to fourth week of March. Safflower aphid infestation appeared from second week of January and remains there up to first week of April, whereas, American bollworm observed from third week of January to first week of March. The highest mean population indicated that thrips were maximum on GS/25 PI-250077, Jassids observed much more on GS/11 PI-262419, White fly on GS/22 PI-401479, aphids were found on GS/19 PI-401476, shoot fly on GS/1 PI-253894 and American boll worm on GS/1 PI-253894. Correlation between environmental factors (maximum, minimum and average temperature as well as relative humidity) and population of all pest species was negative, but whitefly and thrip population with relative humidity showed positive correlation.