** Mosaic disease caused a huge loss in production. Not only did it seriously affect the production of **, but also caused a decrease in the proportion of upper and middle **. It had a great influence on the appearance quality and internal components of ** and reduced the availability of **. Sex, has become the most important factor in the production of **. For the particularly serious ** mosaic disease strains, it is necessary to use pull-ups and to excavate the virus-laden soil away from the tobacco fields. Control has always been very difficult. Cucumber downy mildew, also known as racehorse or rickets, is a serious national disease that can cause most of the leaves to dry in a short period of time. The disease also harms many kinds of melons such as zucchini and pumpkins. Cucumber powdery mildew is one of the common diseases in cucumber cultivation. In recent years, powdery mildew has produced a certain degree of drug resistance, and it can be diseased all year round, which has brought certain difficulties to prevention and control. General incidence will cause a reduction of production by about 10%. For the three plant diseases mentioned above, research on prevention and control has continued and there has been no satisfactory result.

Recently, the Shanghai Academy of Agricultural Sciences invented a p-methoxycinnamic aldehyde emulsifiable concentrate for the control of phytopathogenic fungal diseases and viral diseases. The drug is formulated with an emulsifiable concentrate, which is mixed with p-methoxycinnamaldehyde, vegetable oil emulsifier and soybean oil, and is fully stirred. In specific applications, it is sprayed before the plant plants become diseases. Each active ingredient is 75-300 grams. / Ha, concentration 100 ~ 400μg/ml, spray once every 1-2 weeks, 2 or 3 times in a row. The p-methoxycinnamaldehyde EC is effective against most plant pathogenic fungi, low toxicity, broad-spectrum, systemic absorption and induced plant resistance, and can effectively prevent ** mosaic virus disease (TMV), cucumber downy mildew And the occurrence of cucumber powdery mildew.