According to the overall incidence of pests and diseases in the city in 2007, combined with the layout of planted crops in the Beijing outskirts, the investigation of the overwintering base number of overwintering pests in autumn, and the comprehensive analysis of the weather forecast in spring 2008, it is expected that the incidence of diseases, pests and weeds in the main food crops in 2008 will be moderate overall. More important than disease. Among them, moderate occurrence of insect pests will occur in some areas; grass diseases will occur more seriously; diseases will occur less frequently. I. Trend forecast (I) Insect pests 1. McCain Emphasis was given to the occurrence of an area of ​​about 1.1 million mu, with the locust infestation as the main cause. The main areas: Shunyi, Pinggu, Changping, Tongzhou, Daxing, Fangshan and other plain areas. 2, wheat midge Occurrence of lightness, local partiality occurs, and an area of ​​about 400,000 mu has occurred. The degree of occurrence in the northeastern region is heavier than that in the southern region, and the wheat fields sown with no-tillage are heavier than those ploughed and sown. 3, underground pests The underground pests in the wheat and corn fields are light, and the peanuts and other economic crops are moderate. Occurrence of species is mainly due to dragonflies and golden needles. 4, corn mash Overall moderate occurrence. Among them, one generation of lighter occurrence occurs, and the second generation occurs moderately. Sweet and waxy corn fields will be emphasized. 5, corn thrips, aphids Moderately. Thrips are mainly attacked during spring seedling stage of maize, and corn borers mainly occur during late summer sowing of corn. (B) Diseases 1, powdery mildew, scattered smut Too light occurs, and the area of ​​occurrence will increase from last year. Sensitive breeds, diseased areas and plants with high plant density will occur moderately. 2. Leaf rust, yellow dwarf Leaf rust occurs lightly. Occurrence area will increase compared to last year, mainly in the late growth period of wheat. Wheat yellow dwarf disease occurs locally and mainly occurs after wheat turns green. 3, corn disease The overall situation is mild to moderate, and the damage of spring corn will be heavier than that of summer corn. The main diseases are large patch, small patch, sheath blight, brown patch, and smut. If the summer temperatures are high, more rainfall, and more rainy days, will be conducive to disease. (c) Farmland weeds. The overall emphasis was on development, and the development progress was close to normal. Among them, weeds occur in the wheat field. Bitterweeds such as bromegrass will take place in local wheat fields and tend to expand. Weeds in the corn field tend to occur. (D) Sweet potato disease. In recent years, the planting area of ​​sweet potato in the city has been continuously increasing, mainly distributed in Daxing, Miyun and Shunyi districts. It is expected that sweet potato stem nematode disease will occur more seriously and occur in some areas; sweet potato black spot disease will occur more in parts of Shunyi, and there will be areas Year by year the trend of expansion. (e) Asparagus pests and diseases. Asparagus planting area of ​​6,000 mu, mainly in Miyun County. It is expected that asparagus stem blight will occur more seriously, and individual plots will occur in large numbers. Fourteen o'negative insect pests and other pests will be moderate to overweight. Second, the prediction basis (a) The amount of wintering insects. Except for the wintering base of wheat midge, which is significantly lower than the average value, the wintering bases of other pests are close to or slightly higher than the average of the year, which is favorable for pests. 1. McMug. The overwintering base is higher than the average over the year. In the 70 winter wheat fields surveyed before the winter of 2007, the average amount of 100 stems in the city was 3.6 heads, which was slightly higher than the average of 3.2 heads in the year. The highest plot had a total of 100 heads. 2, wheat midge. Residues and overwintering bases were below average. In the survey of the amount of residues in the middle-to-late May of 2007, the average amount of bivalve insects in the city was 20.8, which was lower than the average of 92 per year, and the maximum amount of terrestrial insects was 362 (control index was 200 per hundred ear insects). A total of 107 wheat fields were surveyed in the autumn scouring survey. The average number of square insects per plant was 0.5, which was lower than the annual average of 49.7. The maximum amount of square insects per square plot was 10.5 (the control index was 2 per square meter). 3, underground pests. In the autumn of 2007, a survey of population density of insect populations in the field covered a total of 70 plots, with an average of 1.2 insects per square meter, and 8 insects per square meter for plots with higher pests (control indicators were more than 3 heads per square meter of wheat). The difference in the amount of insects between plots was large, among which the locust was the main damage, followed by the golden worm. Before the winter survey, the average pest damage rate was 0.7%. 4, corn bran. In the winter of 2007, the average number of live worms in the city was 22.8, which was close to the average of 23.4 since 1985. With the further expansion of spring sown and no-tillage maize planting areas, suitable living environments are provided for overwintering larvae. The amount of straw in the field is beneficial to the overwintering of corn borer, which may cause the survival rate of corn borer larvae to increase. 5, powdery mildew, leaf rust. At the beginning of November, the city carried out autumn seedling surveys on 142 wheat fields, and no diseased plants were found in the fields. 6, farmland weeds. According to the survey of density of weeds in winter wheat fields, the average number of grasses per square meter was 35.1, which was higher than the average value. The average weed density was 465 grasses per square meter, and the grass age was 3-6 leaves. With the annual weeds leeks, sowing wormwood main. (b) The situation of crop growth. Due to the expansion of the treatment of seasonally exposed farmland in Qiuben City, the area of ​​autumn sown wheat has increased significantly compared to recent years. As a result, the area of ​​disease and insect pests in wheat will also expand, and the proportion of late sown wheat sown will be larger, and the crop itself will be resistant to disease. Insect ability declines. In recent years, with the increase in the area of ​​spring sown corn and fresh corn, the occurrence of pests and diseases such as armyworm, corn borer, thrips, and silk black ear has increased. The performance of individual breeds is more sensitive to diseases such as corn borers, thrips, aphids, gray spot disease and Curvularia leaf spot. (c) The weather conditions in the future. According to Beijing's long-range weather forecast provided by the Beijing Climate Center, the average temperature in the spring of 2007-2008 was higher than usual. The winter precipitation was close to normal, and spring was slightly more than normal, which was conducive to the occurrence and damage of spring pests and weeds. Ningxia Black Wolfberry Small Grains,Ningxia Black Goji Berry Small Grains,Ningxia Small Black Goji Berry,Ningxia Samll Black Goji Berry Tea NINGXIA STARLIGHT FOOD TRADE CO.,LTD , https://www.starlightfood.com