Nematodes are important parasites of sugarcane, significantly reducing the yield and the longevity of the crop. Damage caused by them varies with the susceptibility of sugarcane cultivars; thus, it is important for growers to learn the reaction of new genotypes in order to better direct control measures. The objective of this study was to evaluate the damage caused by nematodes to cultivars newly released for commercial planting. Two experiments were conducted in fields infested by Meloidogyne javanica and Pratylenchus zeae. Both experiments were arranged in split-plot randomized block design. The cultivars were planted in the plots, and two carbofuran 350SC levels, 0 and 7 L ha-1, were applied on two subplots (treated and non-treated subplots). On average, the subplots treated with the nematicide had their yield increased by 10%, compared to non-treated subplots, suggesting that nematodes reduced the yield of cultivars by at least 10%, but such a reduction reached 22% for cultivar IACSP97-7569 in experiment 1 and 17% for CTC20 in experiment 2. Damage was insignificant for cultivars CTC9001, CTC9002, IACSP93-3046, IACSP95-5094, IACSP96-3060, IACSP97-4039 and RB975952 in experiment 1 and for cultivars IACSP97-4039, RB867515 and RB966928 in experiment 2. These cultivars can be considered tolerant to hpsMhpshps. javanicahps andhps P. zeae.hps

photoperiod) to carry out laboratory tests to evaluate adult feeding and female oviposition preferences (using both free-choice and no-choice tests) as well as the effects of the cultivars on nymph development and the cultivars tolerance to the pest attack. The least attractive cultivar for adult feeding and oviposition in free-choice test was RB867515, which was also one of those that received the fewest eggs in the no-choice oviposition tests. Cultivar CTC9 showed the highest level of antibiosis resistance, with a root nymph survival rate of 52.5%. Finally, cultivar RB966928 was the most tolerant to M. fimbriolata, but it showed 19% reduction in aboveground biomass weight due to the pest.

The management of nematode infested areas includes several measures, among which chemical nematicides are the most used. However, since their use is associated with environmental impacts, researches with biocontrol agents have acquired a greater importance. This study aimed to evaluate the performance of Bacillus subtilis + B. licheniformis, when applied to the planting furrow, on nematode control and its effects on sugarcane yield. Five experiments were carried out in infested areas, with four treatments: control - no nematicide; carbosulfan 700EC 4 L ha-1 - standard treatment; B. subtilis + B. licheniformis at 0.16 kg ha-1 and 0.20 kg ha-1. Carbosulfan was more efficient in controlling the nematodes, reducing the populations at least four months after planting. The treatments with B. subtilis + B. licheniformis were more effective in the control of Meloidogyne javanica, when compared to Pratylenchus. The plots treated with carbosulfan produced 11 % more than the control. There was no difference between the B. subtilis + B. licheniformis doses, in relation to yield. The plots treated with the biological product produced 5 % more than the control.

Mahanarva fimbriolata (Stål) (Hemiptera: Cercopidae), the sugarcane spittlebug, is one of the most important pests of this crop in Brazil. The magnitude of its damage depends on the pest population, the plants size when they are infested and the cultivar tolerance. The knowledge about those parameters allows the elaboration of the spittlebug management matrix, in which small plants and less tolerant varieties fields are prioritized for sampling and controlling in relation to developed plants and tolerant varieties fields. Therefore, this study aimed to evaluate the response of sugarcane genotypes to M. fimbriolata, so that they can be correctly allocated in the management matrix. Two experiments were carried out under laboratory conditions using a randomized block design with treatments in a factorial arrangement of 2×11 (experiment 1) and 2×21 (experiment 2), with six (experiment 1) or five replicates (experiment 2). The first factor included two levels of infestation (infested and noninfested plants with spittlebugs), while the second consisted of the cultivars. Cultivars IACSP01-5503, CTC 9004 and RB925211 were considered tolerant to spittlebug, they did not show significant reductions in aboveground biomass, despite showing symptoms of pest attack, as leaves yellowing, while CV6654 and IACSP01-3127 were the least tolerant cultivars, showing the highest reduction in aboveground biomass due to M. fimbriolata infestation. Thus, CV6654 and IACSP01-3127 should be prioritized for sampling and control over the others. On average, spittlebug infestations caused 30.9 % of reduction of aboveground biomass.