Controle químico de doenças de Eucalyptus spp. em viveiros e seus efeitos morfofisiológicos

Abstract

Nursery shows microclimatic conditions that favor the development of pathogens that cause serious harm, including death of seedlings. In this way, the integrated management of these diseases becomes mandatory, with various measures that can be taken: asepsis, regulation, biological control and chemical control. The goal of this work was to study the behavior of different pathogens that work in the nursery under different chemicals products, as well the effect of these in the production seedlings, the decreasing of the symptoms level and the possible effect of fungicides on morpho-physiological seedlings. The target of chapter I was evaluate the “in vitro” effect of seven fungicides above the mycelium growing of Botrytis cinerea, Ceratocystis fimbriata, Colletotrichum gloeosporioides Cryphonectria cubensis, Cylindrocladium scoparium, Dothiorella sp., Fusarium solani, Pestalotia sp., Rhizoctonia solani and Quambalaria eucalypti, pathogens to the eucalyptus stakes on concentrations of 1, 10, 100 and 1000 μg.mL-1 (p/v) of active ingredient (i.a) in vehicle BDA. The results showed that the fungicides BAS 516 04 F, BAS 358 01F and BAS 512 14 F six pathogens were partially or completely inhibited at a concentration of 1 or 10 μg.mL-1. In the other side, the fungicide BAS 510 01 F was the less efficient. The Chapter II was to evaluate the different chemicals products in the development of eucalyptus seedlings. In the experiment, was used the clones C041H and P4295H, with two samples of each clone, using six chemical compound. The seedlings was evaluated by air part height (H), basal diameter (DC), weight of total dry mass (MST), weight of dry mass of air part (MSPA), root dry mass weight (MSR), relation between air part height and basal diameter (RHDC) relation between air part height and dry mass of air part weight (RHMSPA) and Dickson quality indices (IQD). In the first sample to the clone C041H, the evaluated parameters did not differ statistically, but in the second sample the best treatment was epoxiconazole and pyraclostrobin. For clone P4295H the best treatments in the first sample were BAS 500 01F and BUC 311 00 F and in the second sample was the absolute evidence, the IQD did not differ statistically for the clone at the two samples. The Chapter III was to evaluate the possible effects of fungicides on the physiological characteristics of two clones of Eucalyptus sp. At 45 days old, the seedlings were evaluated for the photosynthesis rate, transpiration rate, stomatal conductance and internal CO2 concentration. At 70 days old, they were taken to the field and submitted to three evaluations of height and diameter at 30, 60 and 150 days after planting. The physiological parameters were not altered with the use of fungicides as well the height and diameter of clone C041H in the first sample, but in the second sample, the clone has a higher height with the use of the following fungicides, BUC 373 00F and BAS 500 01F. For the clone P4295H in the first sample the best treatments were BUC 311 00F and BAS 510 01F, and in the second sample, the clone had the greatest high at the treatment absolute evidence and epoxiconazole and pyraclostrobin.