Effect of selectivity of herbicides and plant growth regulators used in sugarcane crops on immature stages of Trichogramma galloi (Hymenoptera: Trichogrammatidae)

Herbicides and plant growth regulators are often used in sugarcane management. However, the use of non-selective pesticides can cause adverse effects on the efficiency of beneficial insects in integrated pest management. Within this context, this study aimed to evaluate the effect of such products on the immature stages of the parasitoid Trichogramma galloi. Eggs of Diatraea saccharalis containing the parasitoid at the egg-larva stage and at the prepupal and pupal stages were immersed in test solutions of the following pesticides (maximum recommended doses for sugarcane): herbicides clomazone and diuron + hexazinone, and plant growth regulators trinexapac-ethyl and sulfometuron-methyl. The biological properties evaluated were emergence (F1 and F2) and number of eggs parasitized by T. galloi (F1). The products were classified according to percentage of reduction in emergence and parasitism: harmless (<30%), slightly harmful (30-79%), moderately harmful (80-99%) and harmful (>99%). The pesticides evaluated were considered to be harmless or slightly harmful to immature T. galloi and, thus, their use should be preferred for preserving this parasitoid species in sugarcane management programs.

Management of slips and its effect on growth and production of 'Pérola' pineapple plants

The lack of good quality planting material has limited the expansion and contributed to yield reduction of the Brazilian pineapple culture. Alternatives of 'Pérola' pineapple slips management were studied aiming at obtaining superior planting material within a shorter time period and making good use of healthy slips of low vigor, that are commonly discarded by growers. Two experiments were carried out at the Experimental Field of Embrapa Cassava & Fruits, Cruz das Almas, Bahia, Brazil, and another one in a commercial plantation in the region of Itaberaba, BA, using blocks or entirely randomized designs with at least four replications. In the first one, the development of slips of different initial sizes (6 to 20 cm long), when grown on mother plants after fruit harvest, was compared with that of slips grown in a nursery after their removal from the mother plants. It became clear that larger slips grow more vigorously and that the removal from the mother plant delays their growth. However, results from the second study showed that those slips grown in nursery had vegetative and agronomic performance similar to that of conventional slips and close to that of plantlets produced from plant stem sections. Independently from the type of planting material used, the larger ones presented a more vigorous growth and produced higher yields. In the third study, it was observed the influence of mineral fertilization, pest control and growth regulator application after fruit harvest on slip development. The treatments applied did not significantly accelerate slip growth. Slips reached 50 cm length and at least 300 g fresh weight within 90 days after fruit harvest, indicating that vigorous plants have enough nutritional storage material for slips development.

Sugarcane productivity correlated with physical-chemical attributes to create soil management zone

The socioeconomic importance of sugar cane in Brazil is unquestionable because it is the raw material for the production of ethanol and sugar. The accurate spatial intervention in the management of the crop, resulting zones of soil management, increases productivity as well as its agricultural yields. The spatial and Person's correlations between sugarcane attributes and physico-chemical attributes of a Typic Tropustalf were studied in the growing season of 2009, in Suzanápolis, State of São Paulo, Brazil (20°28'10'' S lat.; 50°49'20'' W long.), in order to obtain the one that best correlates with agricultural productivity. Thus, the geostatistical grid with 120 sampling points was installed to soil and data collection in a plot of 14.6 ha with second crop sugarcane. Due to their substantial and excellent linear and spatial correlations with the productivity of the sugarcane, the population of plants and the organic matter content of the soil, by evidencing substantial correlations, linear and spatial, with the productivity of sugarcane, were indicators of management zones strongly attached to such productivity.