Study On The Species And Control Methods Of Forage Diseases And Insects In Greenhouse

Cultivation of healthy forage plants in the greenhouse is the basis of scientific research,especially in the field of forage pathology.Alfalfa,standing milk-vetch and other forages cultivated in the greenhouse are often damaged by pests and diseases,which greatly affects the accuracy of the research.This thesis researches the types of forage diseases and insect pests in the greenhouse,their prevention,and control to be used in follow-up research.The following main results were obtained:1.Alfalfa(Medicago Sativa L.),standing milk-vetch(Astragalus adsurgens),locoweed species(Oxytropis ochrocephala,Oxytropis kansuensis,and Oxytropis glabra),were cultivated in sterilized soil in a greenhouse(25°C during daytime and18°C at night,12 h light and 12 h darkness).A total of 2 insect pests and 1 disease occurred on Oxytropis kansuensis and Oxytropis glabra.Thrips(Frankliniella occidentalis)caused the leaves to become green,white,and dry.Alfalfa and Oxytropis ochrocephala were the most affected.The larva lives in the soil and eats the rootepidermis,which causes white to yellow-brown and uneven bumps.The adult black diptera insects(Bradysia impatiens)were parasitic on standing milk-vetch and 3species of locoweeds(Oxytropis ochrocephala,Oxytropis kansuensis,and Oxytropis glabra).Fusarium proliferatum was the fungus that caused the plants to weaken,and significantly(P<0.05)reduced the plant height,root length,biomass and leaf transpiration rate,water vapor pressure saturation deficit,net photosynthetic rate,leaf stomatal conductance,as well as,water use efficiency of alfalfa and standing milk-vetch.2.Using 60g/L ethyl spinosyn spray to control thrips on alfalfa has a good effect.The control effect of its 1000 times solution(92.8%)was significantly(P<0.05)higher than 45% imidacloprid microemulsion 2000 times the control effect of the liquid(53.4%).The use of a black light lamp can kill the adult insects which canattract 20~54 heads per day,but the killing of larvae in the soil was the fundamental measure for prevention and control.The use of 100g/L pyriproxyfen 750 times solution(94.4%)has a virtuous control effect(87.4%)than 5000 times of 70%thiamethoxam water-dispersible granules.3.Because the greenhouse is thoroughly sterilized,cleaned,and sealed before starting the experiment,the diseases and insects that occur on plants cultured in the greenhouse may come from outside or are brought in through the air or people.Therefore,before entering into the greenhouse,the experimenter must ensure that there are no pests and diseases.Once they occur in the greenhouse,physical or chemical control is needed to kill them immediately.