Analysis and Control of garlic Diseases in Jinxiang

Editor's note Jinxiang, Shandong Province is the most important garlic producing area in China, and several diseases have been plaguing garlic farmers in recent years. Although many people's analyses have been reported in some newspapers, many of them are ambiguous and beside the point. Recently, this newspaper specially invited teacher Song Yuanlin, a vegetable expert from Shandong Academy of Agricultural Sciences, to conduct a survey among garlic farmers, and now publish the understanding and preliminary conclusions as follows.

The secondary growth of garlic and the phenomenon of bread garlic

When garlic grows to a certain period in spring, the scale buds begin to differentiate, the leaves degenerate, the scale buds gradually form cloves, and the scales outside the degraded buds form the outer skin of cloves, which is the general law of normal growth of garlic. In March, before the garlic is exposed in the garlic vine, 5-6 small garlic leaves grow around the garlic shaft. These leaflets are a long new leaf growing from the outer skin of the new garlic cloves along the garlic stalk, but the growth point of the new garlic cloves does not sprout. This is called garlic degenerated leaf regrowth phenomenon, some are called secondary growth phenomenon, also known as horsetail garlic, Jinxiang garlic farmers call it garlic fork. This phenomenon is the re-growth of degraded garlic leaves when the external conditions are suitable. This phenomenon of leaf emergence has a great impact on the yield of garlic bolts, which is generally reduced by 30%, 40%, and has little effect on the yield of garlic.

The appearance of bread garlic is no different from that of ordinary garlic, but it is lighter in weight. When it is ripe and dried in the sun, it will be pinched with your hands. It is as dry as bread and has no edible value. Some of this phenomenon is called airbag garlic and onion-like garlic, which has a great impact on the yield.

Garlic secondary growth and bread garlic have symptoms in December, generally showing stout and short growth, and can start with secondary growth in March. In March, bread garlic plants grow exuberantly, the plants are thick, and the plants are unusually tall when harvested. The occurrence years of the two kinds of growth anomalies are basically the same, and the estimated causes and control measures are basically the same.

1. In 2003, most of the factors related to the secondary growth and bread garlic were sown at the end of September and the beginning of October, all of which were covered with plastic film. the climate was warmer from the end of February to the first ten days of March 2004, and the garlic began to grow again in late March. The secondary growth and breaded garlic were very serious in that year, and the sowing was more serious relatively early. In 2004, due to the heavy rainfall in autumn, the general sowing was postponed, and most of them were sown in late October. In March 2005, the cold in late spring was serious, and the phenomenon of secondary growth and bread garlic was not very serious. The winter temperature in 2005 is not high, and the secondary growth phenomenon in 2006 is not obvious. The temperature is extremely high in autumn and winter in 2006, the phenomenon of warm winter is extremely obvious, the growth of garlic in winter is too prosperous, the temperature in the first ten days of March 2007 is low, and the cold air of-7 ℃ invades. The secondary growth of garlic and the phenomenon of bread garlic are not obvious in 2007. In the year of serious secondary growth of garlic, the secondary growth and bread garlic phenomenon occurred less in the plots covered with seriously damaged plastic film. In the edge of the ground, border, where the plastic film cover is not good, the secondary growth and bread garlic phenomenon occur less. The phenomenon of secondary growth of urea fertilizer is more serious than that of compound fertilizer.

Second, the reasons for the secondary growth and the phenomenon of bread garlic it is recognized that the physiological factor of the secondary growth of garlic and the occurrence of bread garlic is the overgrowth of aboveground nutrition from February to March, which promotes the re-growth of degraded leaves and leads to the secondary growth and the appearance of bread garlic. Therefore, warm winter, warm spring, excessive application of chemical fertilizer, especially too much nitrogen fertilizer, too early vegetative growth, too late sowing, nutrient concentration in early spring release, plastic film mulching and other factors can lead to the secondary growth of garlic and breaded garlic. Where the secondary growth of garlic and the production of bread garlic are serious, the temperature must be higher from the end of February to the first ten days of March, the garlic will turn green more quickly and the vegetative growth will be more prosperous. Without this condition, although other conditions are available, it will not cause secondary growth and the occurrence of a large number of breaded garlic. Therefore, warm spring is the main reason for the secondary growth of garlic. Warm winter is one of the reasons for the secondary growth and the production of bread garlic. The winter in 2006 is particularly warm, but the phenomenon of secondary growth of garlic in 2007 is not serious, so it can be seen that the warm winter is not the main reason for the secondary growth of garlic and the production of bread garlic. Sowing too late is one of the reasons for secondary growth, but it was generally too late in 2004, which did not lead to serious secondary growth and large number of breaded garlic in 2005. It can be seen that sowing too late is not the dominant factor of secondary growth. Plastic film mulching is one of the reasons for the secondary growth of garlic and bread garlic, but the advantages of plastic film mulching outweigh the disadvantages. Excessive application of chemical fertilizer, especially too much nitrogen fertilizer, is one of the reasons for the secondary growth of garlic and the occurrence of breaded garlic. Related to the variety, the leaf emergence rate of red garlic is high, while that of white garlic is low. Some people think that it is caused by the low temperature and excessive humidity during the storage period of garlic seeds. The garlic seeds in Jinxiang and other garlic producing areas are stored at indoor natural temperature, and the storage temperature is above 20 ℃. There is no phenomenon of low temperature and excessive humidity at all. It seems that this understanding has not been proved in most production practices. It is also thought to be caused by boron deficiency. However, in the same plot, some years occur seriously and some years do not occur without the application of boron. This understanding also needs to be further verified.