| The clover cutworm,(Scotogramma trifolii Rottemberg)is a partially outbreaking pest in farming and stockbreeding areas of northern China. In recent years the pest present uptrend harm to crops. The clover cutworm was often treated as secondary pest with limited studies in China. In order to provide a base for developing integraphic management measures, we study the ecological adaptability of the clover cutworm. The main results were summarized as follows.The investigations were conducted to understand the oviposition preference of host plants by female moth on the 18 plants. These were accomplished by checking and counting the eggs deposited on various crops. Results obtained demonstrated that most eggs were deposited on lambsquarter, followed by sugar beet,cole,potato,corn,sesame,pakchoi cabbage and wheat, eggs were not found on other plants. A large number of eggs are not produced in any of the plants, although insect eggs are usually conductive to the development of their offspring on plants. The reason could be that host plants may not grow well or a variety of host plants close together,or closer together due to various host plant volatiles interference caused insects not recognized host plants and so on. the favorite host plant is lambs quarter for the larvae. followed by the sugar beet,third are cole,amaranth, cabbage. The larvae could transferred from one plant to the other plants during growth such as the first-3 instar larvae do not choose to cabbage, but like cabbage when the 5rd instar.Effects of adult feeding on longevity and fecundity of the female clover cutworm were investigated quantitatively.Adult feeding had significant in influence on both longevity and fecundity of clover cutworm. Females with supplementary food lived longer and deposited more eggs. With deterioration of adult food, longevity was affected more than fecundity. Result of nutritional.deficiency of adult pre-oviposition period extend, oviposition period shortend, eggs decreased. Adults can not complete the normal reproductive process and shortened life expectancy if they are not feeding, however, different nutrition on reproductive and longevity of female moth was not significantly affected. After emergence, female moths in the first 5 to 6 days to reach the peak of spawning. There is no significant difference between the females of flighting and no flighting.Clod hardiness of the clover cutworm was investigated by measuring the supercooling points and freezing points of each development stage. The results showed that the lrd instar larvae to 5rd instar larvae was in an increasing order, lrd instar larvae(-11.36)< 2rd instar larvae (-12.50)< 3rd instar larvae (-11.08)< 4rd instar larvae (-11.05)< 5rd instar larvae (-10.04).There was significant difference between the low instar larvae and old instar larvae while there was no significant difference between the adjacent instar. In the stage of pupae, the supercooling points of diapause pupae (-24.94) was Significantly lower than non-diapause pupae (-21.91), however, female pupae(-23.84) and male pupae(-23.52) had no significant difference. In the stage of adult, female and male had no significant difference too. Changes in the supercooling point was pupae(-23.67)< adult(-15.60)< larva(-11.48), The change showed a significant difference. These finding provided an important basis to determine the overwintering region of the clover cutworm, S. trifolii.
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