Perda de produtividade em feijoeiro comum cultivar Pérola causada por Curtobacterium flaccumfaciens pv. flaccumfaciens

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Two experiments in the field were carried out to evaluate the influence of the initial inoculums levels of Curtobacterium flaccumfaciens pv. flaccumfaciens in the production of bean of the cultivar Pérola. The levels of inocula utilized were of 0%; 5%; 10%; 15%; 20%; 25% and 30% of plants infected with C. flaccumfaciens pv. flaccumfaciens. From a suspension of 2 x 107 ufc/ml inoculations. Were made to reach the desired percentage of infection, in plants after ten days of emergency. The first experiment was sown on 12/11/2004 and harvested on 21/02/2005 named A; the second experiment was sown on 16/12/2004 and harvested on 23/03/2005 named B. It was utilized entirely randomized blocks with three repetitions, each block had seven treatments with three repetitions. Each treatment was composed of three lines of five meters with 0,5 m between them and a density of plantation of 12 seeds per linear meter. The results were analyzed at the end of the cycle of the culture, comparing the productivity presented in each level of inoculum with the productivity of the control (0% C. flaccumfaciens pv. flaccumfaciens). According to the results obtained in the experiment A, the average bean production for each treatment was 1170,0 g; 1118,9 g; 1054,0 g; 1053,3 g; 1032,2 g; 976,7 g; 892,2; for 0%; 5%; 10%; 15%; 20%; 25% and 30% of plants infected, corresponding a reduction of 0%; 4,4%; 5%; 9,9%; 11,8%; 16,6% and 23,8% respectively. In the experiment B the average bean production for each treatment was 658,9 g; 581,1 g; 515,5 g; 492,2 g; 462,2 g; 417,8 g; 351,1 g for the same rates of infection and with a reduction of 11,8%; 21,8%; 25,30%; 29,98%; 36,6% and 46,7% respectively. A survey was carried out in the years of 2004 and 2005 in commercial plantations in the Federal District (PAD DF), Goiás (Cabeceiras) and Minas Gerais 9 (Buritis) in a range of approximately 200 km from Brasilia, and the presence of the bacterium was detected in 100% of the visited farms. Two experiments (B1 and B2) were carried out in the greenhouse utilizing seeds from a bean field C. flaccumfaciens pv. Flaccumfaciens, with the objective of evaluate the sanity during 60 days. The experiments showed 80,7% and 76,6% respectively of the plants with some kind of symptom caused by Curtobacterium flaccumfaciens pv. flaccumfaciens. Persistence and viability of C. flaccumfaciens pv. flaccumfaciens was evaluated in soil collected in a bean field area under central pivot with occurrence of high levels of infection bacterial wilt in and the results indicated that, at least during ten months, period of duration of the experiment, the bacterium remained viable and able to infect beans plants. Based on the results it is possible to affirm that the Curtobacterium wilt is widely disseminated in the region of the Federal District and vicinity, can cause significant losses of productivity in the culture of bean and persists in the soil and crop debris for at least ten months.

ASSUNTO(S)

murcha de curtobacterium fitopatologia perda de produtividade murcha do feijoeiro níveis de inóculo

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