Screening And Mechanism Investigation Of Colored Plastic Film For The Control Of Delia Antiqua(Meigen)

Delia antiqua is an underground pest with wide distribution causing serious economic losses in China.It mainly damages Liliaceae crops such as garlic and scallion,resulting in a serious reduction in crop quality and yield.Garlic is an important vegetable crop in China,and Shandong Province is the main production area of garlic.In recent years,D.antiqua have caused serious economic losses in garlic production.At present,chemical measures are mainly used to control the D.antiqua in production,which leads to the increase of insecticide resistance and pesticide residues,and the decrease of food safety.The technology of colored film mulching develops rapidly.Significant effects have been achieved in increasing yield and efficiency of various crops,but there are few studies on the effect of pest control,and the effects of colored film on the occurrence of D.antiqua has not been reported.To screen highly efficient colored film in controlling Delia antique,this paper studied the populations of D.antique in garlic fields mulched with six kinds of color plastic film and the adult behavior,longevity,fecundity and larval growth of D.antique under different color circumstances.Then the effects of light on the repellent response,activity behavior,reproduction and longevity of the adult were analyzed to explore the function of colored film.It provides theoretical basis and technical support for promoting the physical control of D.antique.The main results are as follows:1.By field investigation,the colored film with insect control effect was screened out.The results showed that silver-gray film could significantly reduce the number of D.antiqua,silver-black film was the second,and red film was also significantly lower than the control film.Compared with transparent film,the population of silver-gray,silver-black and red film decreased by 69.31%,42.08% and 34.65%,respectively.Whereas,blue and black film would aggravate the occurrence of D.antiqua,and the population increased by 123.27% and 50.99%,respectively.2.The effects of colored film on the selectivity of adults of D.antiqua were determined,the repellent effect on the adults is the important reason leading to the decrease of the population in the field.In garlic fields,the selection rates of D.antiqua on silver-gray,silver-black and red film were 5.28%,9.47% and 10.85%,respectively,which were obviously lower than 15.24% for that of the transparent film.Whereas the selection rates of blue and black film were 37.81% and 21.35%,respectively,which were significantly higher than the control.The results of the indoor selective assay were consistent with those in field experiments.The effect of colored film on the larvae of D.antiqua was studied.The results showed that the growth and development of the D.antiqua under silver-gray film was significantly faster than that under transparent film.There was no significant difference in the growth and development of silver-black film,but the growth and development of black film decreased significantly.3.The effects of colored film on the behavior,longevity and fecundity of the adults of D.antiqua were determined.The silver-gray and silver-black film affect the activity of the adults on the film and have a negative effect on longevity and fecundity.Compared with transparent film,the silver-gray and silver-black film significantly increased the frequencies of crawling and flying of the D.antiqua.And the life of female adults with silver-gray and silver-black film were reduced by 2.13 d and 2.53 d,the number of eggs laid per female decreased by25.43% and 22.38%,the egg hatching rates decreased by 20.48% and 11.14%,the numbers of effective offspring decreased by 40.23% and 30.18%,respectively.There was no significant difference in the occurrence rate of adult behavior of D.antiqua with the blue film,but the egg hatching rate and the number of effective offspring were significantly increased.4.The repellent effect of the main reflectance spectrum of the colored film on the adult of D.antiqua was studied.Compared with the white light control,the repellency of ultraviolet light was significantly increased,followed by red light.Under 1000 lx light intensity,the repellent rates of female D.antiqua on ultraviolet and red light were 74.44% and 60.26%,respectively,which were significantly higher than 24.49% of the control.And the repellent rates of male D.antiqua on ultraviolet and red light were 78.89% and 66.34%,respectively,which were significantly higher than 26.82% of the control.The results of light intensity increasing test show that,in the range of light intensity from 200 lx to 1000 lx,the repellency of D.antiqua increased with the increase of light intensity.The Photophobia rate of male was higher than that of female,and mating would affect the light avoidance of female,the photophobia rate of the female increased after mating;starvation could enhance the photophobia rate of the D.antiqua.5.The repellent wavelengths of ultraviolet and red light affected the behavior of the adult,and had adverse effects on its longevity and fecundity.Compared with the control,the incidence of crawling and flying activities increased significantly,while the incidence of mating behavior decreased significantly.The longevity and fecundity of the D.antiqua were significantly inhibited under ultraviolet and red light.Compared with white light,the life of female adults with ultraviolet and red light were reduced by 4.60 d and 3.73 d,the life of male adults were reduced by 3.20 d and 2.74 d,the number of eggs laid per female decreased by41.27% and 31.14%,the egg hatching rates decreased by 45.00% and 36.00%,the numbers of effective offspring decreased by 67.53% and 55.84%,respectively.