Bulb Plants Occurrence Of Pepper Blight

Chemical control is still the main method to control Phytophthora capsici, but non-pollution and organic agricultural products is the direction of development. In present study, effects of garlic, welsh onion, scallion crude extracts on P. Capsici growth and disease control, the effect of disease control in garlic, shallot, scallion, bell pepper crop rotationand and companion planting were investigated. Using Solid phase micro-extraction GC-MS, volatile components of garlic, shallot, scallion was analyzed. Effect of exogenous thioether organic sulfides which is the Main Chemical Constituents of these volatile components on P. Capsici growth was studied. The main results are as follows:1. The crude extracts that from different parts of allium had significant inhibitory effect on P. Capsici growth.The crude extracts of allium had significant inhibitory effect on P. Capsici growth from plate antibacterial test. With the increasing concentration, the inhibiting effect of P. Capsici growth would be greater. But, with the increment of culture time of P. Capsici, the inhibiting effect of P. Capsici growth would be greater was decreased somewhat. In addition, there were significant difference in the inhibitory rate of P. Capsici growth among the crude extracts of different allium. The highest inhibition rate of P. Capsici growth was found in garlic’s bulb antibacterial, which reach100.00%in the concentration level of150mg/ml, the secondly for garlic roots and shoot. However, the crude extracts of shallot and scallions have the lowest inhibitory effect. In the concentration level of300mg/ml,inhibitory rate of the crude extracts of shallot and scallion on P. Capsici growth reach78-88%.2. The crude extracts that from allium, as well as the crop rotation systems and intercropping of allium, which have significant inhibitory effect on P. Capsici growth.Pot experiments show that the crude extracts that from different parts of allium, as well as the crop rotation systems and intercropping of allium, which have significant inhibitory effect on P. Capsici growth. Among them, crude extracts of garlic’s bulb had the highest control effect. In the concentration of150mg/ml, the disease prevention level of crude extracts of garlic’s bulb reach59.38%. the secondly for garlic’s root. However, extracts of shallot and scallion have near control effects with garlic only when its concentration is as high as300mg/ml. The crop rotation systems of garlic, shallot, scallion showed a good control efficacy on P. Capsici. In the crop rotation systems, garlic has the highest control effect which reach59.81%. But, shallot has the lowest control effect which reach40.67%.The intercropping of garlic has the highest control effect, which reach62.09%.But, shallot has the lowest control effect which reach41.21%.3determination of volatile component of different parts of Garlic, shallot and scallion by the GC-MSThe study proves that there are28kinds of volatile components in shallot stems and leaves, Organic sulfides accounted for82.17%and the disulfide accounted for23.39%.14kinds of volatile components of shallot’s root accounted for99.4%of organic sulfides, disulfide accounted for83.18%. There are27kinds of volatile components in scallion’s stems and leaves, Organic sulfides accounted for85.92%and the disulfide accounted for37.45%.20kinds of volatile components of scallion’s root accounted for97.22%of organic sulfides, disulfide accounted for27.7%. Stems and leaves of shallot and scallion mostly contain monosulfide2,4-dimethyl thiophene, roots mostly contain disulphide dipropyl disulfide and other sulfide compounds. Organic sulfur compounds accounted for90.65%in20kinds of volatile components of garlic’s stems and leaves, disulfide accounted for60.66%. Organic sulfur compounds accounted for92.14%in22kinds of volatile components of garlic’s root in disulfide accounted for60.31%. Organic sulfur compounds accounted for92.85%in23kinds of volatile components of garlic’s bulbs, disulfide compounds accounted for59.18%. In generally, the main component of Garlic’s stems and leaves, roots, bulbs is sulfide compounds.4Effects of P. Capsici growth in medium addeddiallyl trisulfide, diallyl disulfide, diallyl sulfide, methyl-2-propenyltrisulfide, was studied.The results showed that diallyl trisulfide, diallyl disulfide, diallyl sulfide, methylpropyl disulfides has significant inhibitory effect on P. Capsici growth. With the increasing concentration, the inhibiting effect of P. Capsici growth would be greater.