Method for identifying survival state of plant pathogenic nematode larvae in activity determination of nematicide

Abstract

The invention provides a method for identifying the survival state of plant pathogenic nematode larvae in activity determination of a nematicide. The method comprises the following steps of: mixing second-instar larvae of root-knot nematodes with liquid medicine for incubation by adopting a post-drug body length measurement method for the first time, setting blank control by adopting the same batch of larvae, and then performing photographing to observe the body state of the larvae, and measuring the body length of the second-stage larva of the root-knot nematode, and identifying the survival state of the bent and irregular S-shaped larva through the shortening rate of the body length of the larva. The method for identifying the survival state of the plant pathogenic nematode larvae is easy and convenient to operate, the survival state of the larvae which are bent to be in an irregular S shape can be judged only by measuring the shortening rate of the body length of the larvae, the accuracy is high, the survival state of the larvae treated by drugs with different concentrations can be accurately identified, and misjudgment of dead and living of nematodes is avoided.

Description

technical field [0001] The invention relates to the technical field of pesticide screening, in particular to a method for identifying the living state of plant pathogenic nematode larvae in the determination of nematicide activity. Background technique [0002] Hainan Province belongs to the tropical monsoon climate zone, with suitable temperature, loose sandy soil, and sufficient water source. Nematode (Meloidogyne spp.) disease is particularly serious. Root-knot nematodes damage the roots of vegetables and form root knots on young roots and fibrous roots. Severely diseased plants are short, with yellow leaves, lack of fertilizer in spots, and weak or poor fruiting. The agricultural loss rate caused by such nematodes in the world is 11% to 25%. In China, nematode disasters have occurred seriously year after year, and the area of ​​occurrence and the types of crops have been increasing. According to incomplete statistics, the annual agricultural loss caused by nematode dam...

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Problems solved by technology

At present, the control of plant root-knot nematodes is still dominated by chemical control. In order to screen out pesticides with good control effects on plant nematodes, the insect soak method (NY / T1833.1-2009) is often used to measure the activity of pesticides on nematodes, and the accuracy Judging the life and death of nematodes is the key to bioassays, but in the research, it is often found that the dead state of nematodes after chemical treatment is various, some are stiff, some are bent in an irregular "S" shape, and the larvae in the stiff state are all dead insects, " The S” shape is very similar to live worms, which can easily lead to misjudgment; currently, the commonly used nematode life-and-death identification methods include: dead state visual inspection method and stimulation method, which are easy to operate but have large human errors; dyeing method, sodium chloride method, The dyeing excitation light method is accurate in judgment but the operation is cumbersome, and the dyeing excitation light method has high requirements for the instrument, such as patent CN101149366 "A New Method for Rapid Quantification of Nematode Mortality", patent CN105911035A "A Rapid Identification of Meloidogyne incognita Method for Second Instar Larva Survival Status in Vitro"; Therefore, it is necessary to seek a method for judging the life and death of nematodes with simple operation and high accuracy

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