The present research describes the defensive behavior of Haplostegus nigricrus Conde (Hymenoptera: Pergidae) larvae exposed to the stink bug predators Podisus nigrispinus (Dallas), Supputius cincticeps (Stal) e Brontocoris tabidus (Signoret) (Heteroptera: Pentatomidae). The main defensive strategy of H. nigricrus seems to be the regurgitation of toxic compounds and the continuous exhibition by the mouth, because all predators died until 24 hours after the direct contact. Only B. tabidus reached the adult phase with H. nigricus larvae as diet what suggests the higher tolerance and hability for detoxication of chemical compounds from that Symphyta.

The aim of this paper was to evaluate the genetic divergence of a melon population of the Plant Breeding Program from the Federal University of Alagoas. The following quantitative characteristics were evaluated: the fruit weight (FW), the longitudinal fruit (LFL) and transversal fruit (TFL) lengths; the skin (SFT) and the pulp¿s (SPF) thicknesses; and number of seeds (NSF). For the evaluation of the genetic divergence, a multi varied analysis was used by means of the main component method, which graphical dispersion was done from the two first components and from the euclidean distance average standardized, being that the grouping among the similar families done by the Tocher Method. The results suggest genetic divergence among the families, indicated by the two techniques used. The two first main components were able to explain 72.36% of the existing variability, being the TFL and FW variables which contributed more to the divergence. Considerable genetic divergence among the families was verified and that some of these are promises for use in genetic improvement programs.

This study aimed at knowing the diversity of fruit fly species (Diptera: Tephritidae) and discussing the influence of abiotic factors on the population fluctuation of these species on a guava (Psidium guajava L.) orchard in Russas, CE. Two McPhail traps baited with protein hydrolisate at 5% were set up on the orchard. The traps were serviced weekly and all the insects captured were transported to the laboratory where the fruit flies were separated from other insects, counted and preserved in alcohol (70%). The survey was carried out from January to December 2003. Tephritids were identified at the Laboratório de Moscas-das-Frutas at UFERSA, in Mossoró (RN). Population fluctuation was calculated based on the number of flies/trap/day, considering the total number of males and females of Anastrepha and Ceratitis. Climate data used in this study were obtained from CENTEC weather station. The correlation between population fluctuation and abiotic factors was analyzed using Spearman correlation coefficient at the 5% level. A total of 1,164 fruit flies belonging to four species were captured - Anastrepha zenildae Zucchi (77.45%), A. sororcula Zucchi (18.69%), A. obliqua (Macquart) (0.15%) and Ceratitis capitata (Wied.) (3.71%). Among the abiotic factors, temperature and relative humidity were the ones that most indirectly influenced the population fluctuation of fruit flies. However, the availability of host fruits is the preponderant factor that determines the populational peaks of fruit fly species throughout the year on this guava orchard in Russas (CE).

The water and soil natural resources in the semi-arid tropics are under pressure and are inclined to degradation due to the severe environment and shallow soils, in ecologically sensitive regions to anthropic actions. In view of the above, this work aimed to characterize the structure and the hydraulic evaluation of the surface water typical of interrill erosion, in a caatinga area of Serra Talhada country in Brazil. For this the quadrant point method was used in the structural characterization of the vegetation of caatinga for trees and shrubby species. Laminar surface regime was generated from a rain simulator in 2 m2 plots with caatinga in the humid and dry seasons. The differentiations of the flow rates, average surface water speed and the Reynolds number, had demonstrated the significant effect of seasonality on the characteristic laminar surface water of the interrill erosion. The observed tree-shrub structure of caatinga contributed to the low values of runoff coefficient of the interrill areas, demonstrating the efficiency of caatinga, and its resulting vegetated cover in the interception of rain and, in the delay of the surface water. The low values runoff also observed also contributed to the high rates of infiltration of water.

Corn yield losses caused by weeds may reach up to 80%. Reducing the use of herbicides is one of agriculture's major goals and several alternatives are currently being investigated, including intercropping. In the Brazilian Northeast, corn intercropping with cowpea (Vigna unguiculata (L.) Walp.) is extensively practiced, and there is interest in evaluating weed control under this type of intercropping. The objective of this work was to evaluate the effects of different cowpea planting times, intercropped with corn, on green ear yield of two corn cultivars. The experiment was carried out under randomized design blocks with four replications. AG 1051 and AG 2060 corn cultivars were submitted to the following treatments: no hoeing, two hoeings (20 and 40 days after planting), and cowpea planting (BR 4 - Mulato cultivar, with indeterminate growth) at corn planting and at 5, 10, and 15 days later. Twenty-eight weed species were found in the experiment area. In all characteristics evaluated, except for plant height, ear height, and total number of green ears, where no difference occurred between treatments, the lack of weeding determined the smallest means, while weed control determined the highest. In plots where cowpea was sown, intermediate means were obtained for number and weight of marketable unhusked green ears and for number and weight of marketable husked ears. This suggests that cowpea controlled weeds to a certain extent, especially when it is planted earlier, which was, however, insufficient to avoid green ears yield loss. The corn cultivars evaluated were not different among themselves, except with regard to ear height. The cowpea grain yields were practically null in all plots.

The experiment was carried out at Plant Health Department of the Escola Superior de Agricultura de Mossoró, ESAM during the period of October to November of 2003, with the objective of evaluating the effect of different saline solution leveis on seed germination and development of seediings of song-thrush (Mimosa caesalpiniiflolia Benth.). A completely randomized experimental design was used with four treatments and four replicatíons of fifty seeds. The treatments consísted ofthree saline solutions (of 10, 20 and 30 dS/m) pius a control (0.614 dS/m). The seeds were incubated in sterilized sand into wood packing-case. The evaluated traits were emergency percentage, Índex of emergency speed, seediing height, number of leaves and seedlings fresh and dry mass. The increase of the leveis of solution salinity decreased the seediing height and Índex of emergency speed, besides of influencing on seed emergency percentage.

Nematodes are abundant metazoans in all ecosystems with some species surviving in extreme conditions. The sand dunes are dynamic systems and are always in a state of successional change in terms of succession and only recently has the distribution and succession of soil animals in coastal dunes been given wider attention. This research focused on to describe the trophic structure of nematode community associated with two stages of a vegetation succession in a coastal moving sand dunes ecosystem in the north shore of the Rio Grande do Norte State. Five sites were classified in two stages of an ecological succession defined as "beach" and "deflation hollows among dunes" where samples of soil, roots and shoots were collected. Nematodes were extracted from the soil by centrifugal flotation procedure and from the roots by this method associated to blender trituration and classified in families and trophic groups according to feeding habits. The structure of nematode fauna was described by maturity index, plant parasite index and modified maturity index and fungal feeders/bacterial feeders and omnivores+predators/bacterial feeders+fungal feeders+plant parasites rates. The ecosystem was characterized by low diversity of families which composed trophic groups, low values of maturity indexes and omnivores+predators/bacterial feeders+fungal feeders+plant parasites ratio and low abundance of dorylaimids. These datas reflected high level of disturbance which this habitat faces.

To have high yields it is necessary that seed of good quality be sowing and, to produce them, mother plants should receive appropriate treatment, like fertilization. Aiming evaluate how copper and zinc fertilization, in three types of soil, and its influence in physiological quality of sorghum seeds, in an experiment in randomized blocks with tree replicates. The treatments were a combination of five levels of Cu (0,0; 0,26; 0,90; 1,54; 1,80 mg kg-1 of soil) and five levels of Zn (0,0; 0,32; 1,10; 1,88; 2,20 mg kg-1 of soil), resulting in nine treatments in experimental matrix Central Box. Seeds produced were analyzed of hundred seed weight, germination and vigor (germination first count, IVG, emergence, emergence first count, IVE and seedlings dry matter). The levels of copper and zinc increased hundred seed weight and vigor tests. Plants cultivated in Haplustalf produced seed with the best quality.

The experiment was carried out to determine the effect of intermittently drain tilapia ponds for vegetable irrigation. A completely randomized design in a factorial arrangement 2X3, with three replications was used in this experiment. The first factor was kind of feed: feed 1 - without animal ingredients; feed 2 - with the inclusion of shrimp meal; and feed 3 - with the inclusion of fish meal. The second factor was pond drainage scheme, where in the scheme 1, ponds were intermittently drained for irrigation and subsequently refilled; and in the scheme 2, ponds were not drained. Sexually reversed Nile tilapia (Oreochromis niloticus) with average weight of 1.66 g were randomly stocked at the experimental ponds, with thirty five fish per tank, in a stock density of 1.25 fish per m2. Fish were fed two times a day in a proportion of 5% of body weight. There was a significant effect for tank drainage scheme for the variables feed conversion ratio and survival (P<0.05) where tilapias cultured on ponds intermittently drained for irrigation had higher survival and better feed conversion ratio. There was no significant effect (P>0.05) on the interaction between kind of feed and tank drainage scheme for any of the studied variables. Feed type and pond drainage scheme had no effect on weight gain (P>0.05). Therefore, it can conclude that intermittently drained fish ponds, for irrigation, results in the best tilapia's performance in terms of feed convertion and survival.

The quality of irrigation water is one of the environmental factors that can affect the initial growth of the culture of melon. This study aimed to evaluate the emergence of seedlings of melon, hybrids Goldex and Vereda in different levels of salinity of irrigation water. The study was carried out at the Seed Analysis Laboratory of the Department of Crop Science of the UFERSA, Mossoró, RN, between February and April 2007. The treatments were organized in a completely randomized design in factorial scheme 2 x 6 (two hybrids of melon plant Goldex and Vereda, and six levels of electrical conductivity of irrigation water: 0,45; 1,30; 2,15; 3,00; 3,85; 4,70 dS m-1), with four replications. Evaluation of speed of emergence-index, height of the aerial part of the seedling, dry mass of the aerial part of the seedling and seedling emergence. The salinity interfered in all parameters measured, and that as of 2.5 dS m-1 were more harmful to the hybrid Goldex that Vereda.