The sugarcane borer, Diatraea saccharalis (Fabr., 1794) (Lepidoptera: Crambidae), is one of the main pests of sugarcane. This pest can reduce the quality and yield of the crop. Information on the quality and yield of cultivars in relation to the attack of sugarcane borer are necessary, since they guide the choice of the best materials for use in joint with other management tactics. Two field experiments were conducted in 2011 and 2012 to compare the quality and yield of 16 commercial sugarcane cultivars (IACSP93-3046, IACSP94-2094, IACSP94-2101, IAC91-1099, IACSP95-5000, IAC87-3396, RB92579, RB867515, RB966928, CTC2, CTC4, CTC9, CTC11, CTC15, CTC18 and SP86-0042) relative to the natural infestation of D. saccharalis. The experimental design was a randomized complete block with four replications. There was no difference between treatments for infestation index, with averages of 1.2 to 8.7% of bored internodes. Higher percentages of internodes with red rot were observed for CTC9, CTC2 and RB966928. The cultivars CTC4 and RB92579 infested with D. saccharalis resulted in lower technological quality, due the reduction in the contents of brix, apparent sucrose content (POL) and purity; and increase of the reducing sugars and, consequently, lower theoretically recoverable sugar (TRS). On the other hand, the lowest yields (t of cane ha-1) were observed for CTC18, IACSP94-2094, IACSP94-2101 and RB966928. Therefore, according to the hierarchical cluster analysis (UPGMA), the cultivars RB867515, CTC11, IAC91-1099, CTC15, SP86-0042, CTC2 and IACSP94-3046 were resistant to D. saccharalis.

SUBSTÂNCIAS HÚMICAS E FONTES DE FÓSFORO NA CULTURA DO MILHO O objetivo do estudo é verificar o efeito da adição de doses de um produto comercial a base de substâncias húmicas (SH), na produção de massa seca de plantas de milho, no acúmulo de P nas plantas e a eficiência agronômica de fontes de fósforo em dois tipos de solos com diferentes capacidades de adsorção. O trabalho foi conduzido em casa de vegetação. Os tratamentos compreendem quatro doses de substâncias húmicas (0, 100, 200 e 400 kg ha-1) e duas fontes de fósforo (superfosfato triplo – SFT e fosfato natural reativo – FNR), em dois tipos de solos (Latossolo Vermelho – LV e Neossolo Quartzarênico – NQ). As fontes de P foram fornecidas em dose constante de 75 mg.dm-3 de P. Houve resposta estatisticamente significativa (P<0,05) da produção de massa seca da parte aérea (MSPA), massa seca das raízes (MSR), P acumulado na parte aérea e P acumulado nas raízes à adição de SH. No LV os parâmetros MSPA, MSR, P acumulado na parte aérea, P acumulado nas raízes e a Eficiência agronômica relativa das fontes de P aumentaram com a adição crescente de SH, obtendo os melhores resultados com uso da maior dose (400 kg ha-1). No NQ as melhores respostas foram obtidas com a adição de 100 kg ha-1 da SH. Estes resultados indicam que a utilização de substâncias húmicas é eficiente para o aumento da produção de massa seca das plantas de milho e no teor de P acumulado.Palavras-chave: P acumulado, eficiência agronômica relativa, adsorção de fósforo. ABSTRACT: The objective of this study was to verify the effect of the application of different rates of a commercial product based on humic substances (HS) on the dry matter contents, and P accumulation in maize plants and the agronomic efficiency of phosphorus sources in two soils with different adsorption capacities. The experiment was conducted in a greenhouse. The treatments consisted of four rates of humic substances (0, 100, 200, and 400 kg ha-1) and two phosphorus sources (triple superphosphate – TSP; and reactive natural phosphate – RNP) in two types of soils (Rhodic Hapludox – RH; and Typic Quartzipsamment – TQ). The response of the shoot dry weight (SDW), root dry weight (RDW), shoot accumulated P, and root accumulated P to the application of HS was statistically significant (P <0.05). In the RH, the SDW, RDW, shoot and root accumulated P, and relative agronomic efficiency of the P sources increased with increasing HS rates; thus, the best results were found with the use of the highest rate (400 kg ha-1). In the TQ, the best responses were found with the application of 100 kg ha-1 of HS. These results indicate that the use of humic substances is efficient to increase dry matter and accumulated P contents in maize plants.Keywords: accumulated P, relative agronomic efficiency, P adsorption.

The productivity of upland rice increases with the number of plants per unit area to the point where intraspecific competition for nutrients, water, light and other factors of production limits the productive process. The objective of this work was to evaluate the effect of spacing on the production of highland rice irrigated in the brazilian savannas. The experiment was conducted from May to October of the year 2015 in Goianésia -GO, in the experimental area of the Evangelical Faculty of Goianésia. The BRS Primavera variety was tested in four spacings (20, 30, 40 and 50 cm) between rows and density of 100 seeds per meter and used as sprinkler irrigation. The experimental design was in randomized blocks, with four treatments with three replicates. The results showed that the spacing of 30 cm between rows provided higher productivity in the BRS Primavera variety.