The Effect Of Different Tillage Methods And Insecticide Treatment On Severity Of Maize Ear Rot And Contamination Levels Of Fumonisins In Maize Kernels

Maize ear rot is not only a worldwide maize disease but also the important disease on maize production in China. Fusarium verticillioides that causes maize ear rot is the main pathogenic bacteria, and not only directly causes losses of maize yield but also fumonisins that is produced by Fusarium verticillioides affects the quality of maize. In this paper, Fusarium verticillioides and Fusarium graminearum are used as the selected pathogens, under the condition of artificial inoculation, and to study the effect of different Fusarium interactions on severity of maize ear rot and contamination levels of fumonisins in maize kernels; another effect is studied for different planting densities, different fertilizer consumptions, different tillage methods, and insecticide on severity of maize ear rot and contamination levels of fumonisins in maize kernels; In addition, the systemic monitoring for the natural occurrence of FB1 and FB2 in maize samples from Hebei, Liaoning, Shandong, Henan, etc. and a total of 17 provinces and autonomous regions in 2012 as well as for the natural occurrence of FB1 and FB2 in maize samples from Hebei, Liaoning, Shandong, Henan, Shanxi, Inner Mongolia and a total of 6 provinces and autonomous regions in 2013. The results are as follows:1.The severity of maize ear rot and contamination levels of fumonisins in maize kernels for Xianyu335 is more serious than Zhengdan958 and Xundan20 in all the selected maize varieties. Xianyu335 is more susceptible to maize ear rot than Zhengdan958 and Xundan20.2.Whether separately or together inoculate Fusarium verticillioides and Fusarium graminearum, all can make severity of maize ear rot become more serious and contamination levels of fumonisins in maize kernels become higher.3.The effect is not obvious for order of mixed inoculation on severity of maize ear rot and contamination levels of fumonisins in maize kernels. Fusarium graminearum may exist certain inhibition for the production of fumonisins from Fusarium verticillioides. The field climate conditions such as rainfall, temperature and relative humidity exist certain influence on severity of maize ear rot and contamination levels of fumonisins in maize kernels. Higher rainfall, higher temperature as well as higher relative humidity is more conducive to the occurrence of maize ear rot and the accumulation of fumonisins in maize kernels.4.The different planting densities, fertilizer consumptions, tillage methods, and insecticide exist certain influence on severity of maize ear rot and contamination levels of fumonisins in maize kernels, but there is no significant difference. With the increase of planting density and fertilizer consumption, the severity of maize ear rot for Xianyu335 and Xundan20 also increase gradually; planting density and fertilizer consumption have no significant influence for the contamination levels of fumonisins in maize kernels of Zhengdan958 and Xundan20; the severity of maize ear rot of direct sowing is higher than rotary tillage for Xianyu335 and Xundan20, but there is no significant difference for the contamination levels of fumonisins in maize kernels; insecticides could mitigate the severity of maize ear rot and reduce contamination levels of fumonisins in maize kernel.5.In 2012, 299 of 596 maize samples show contamination of fumonisins, the incidence of fumonisins is 50.2%, the mean contamination level of fumonisins is 1575 ng/g; the contamination level of fumonisins is relatively lower for maize samples from the northwest provinces including Xinjiang, Gansu, Ningxia, Inner Mongolia, Shanxi, but located in the southwest, the huang-huai-hai region and the surrounding provinces such as Yunnan, Shandong, Liaoning, etc., the maize samples exist higher contamination levels of fumonisins.6.In 2013, 133 of 188 maize samples show contamination of fumonisins, the incidence of fumonisins is 70.7%, the mean contamination level of fumonisins is 5225 ng/g; there is significant difference for the incidence and contamination level of fumonisins in different regions and years; the contamination level of fumonisins is relatively higher for the huang-huai-hai region as well as the surrounding provinces such as Shandong, Henan, Hebei and Liaoning, but located in the northwest provinces as well as the surrounding provinces such as Inner Mongolia and Shanxi, the maize samples exist relatively lower contamination level of fumonisin.7.Different years have different contamination levels of fumonisin for different regions. The contamination level of fumonisins in 2012 is higher than that in 2013 for Shandong province; the contamination level of fumonisins in 2012 is lower than that in 2013 for Liaoning, Henan, and Hebei province.