The selectivity of five insecticides, regularly used in peach farming, was assessed for larvae of the predator Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) by means of bioassay in semi-field conditions. The bioassay was based on the counting of captured larvae after release in peach trees treated with the insecticides (% of active ingredient in spray liquid): deltamethrin (0.001), fenthion (0.050), phosmet (0.100), lufenuron (0.005) and malathion (0.200). Bait-cards with eggs of Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae) were used to capture larvae from treated plants; five of them were fixed in plant canopy and five others left on the soil around stem. A protective barrier made up of galvanized steel sheet was used for each plant to avoid loss of larvae. The number of larvae feeding on the bait-cards was measured for four days. According to the number of captured larvae, each insecticide effect was estimated and classified into toxicity categories as stated by the International Organization for Biological and Integratec Control of Noxious Animals and Plants (IOBC). Based on observations, the insect growth regulator lufenuron was harmless, while the neurotoxins deltamethrin and malathion were slightly harmful; and lastly, fenthion and phosmet were moderately harmful to C. externa larvae in semi-field conditions. Thus, lufenuron should be recommended for integrated pest management, since it would preserve this predator species in peach orchards.

Cacao (Theobroma cacao L.) is an important fruit in the Brazilian economy, which is mainly cultivated in the southern State of Bahia. The optimal stage for harvesting is a major factor for fruit quality and the knowledge on its growth curves can help, especially in identifying the ideal maturation stage for harvesting. Nonlinear regression models have been widely used for description of growth curves. However, several studies in this subject do not consider the residual analysis, the existence of a possible dependence between longitudinal observations, or the sample variance heterogeneity, compromising the modeling quality. The objective of this work was to compare the fit of nonlinear regression models, considering residual analysis and assumption violations, in the description of the cacao (clone Sial-105) fruit growth. The data evaluated were extracted from Brito and Silva (1983), who conducted the experiment in the Cacao Research Center, Ilheus, State of Bahia. The variables fruit length, diameter and volume as a function of fruit age were studied. The use of weighting and incorporation of residual dependencies was efficient, since the modeling became more consistent, improving the model fit. Considering the first-order autoregressive structure, when needed, leads to significant reduction in the residual standard deviation, making the estimates more reliable. The Logistic model was the most efficient for the description of the cacao fruit growth.

Fruit thinning is the removal of fruitlets in heavy fruit set situations and aims to increase salable fruit sizes, avoid branch breakdown, reduce harvesting costs, and promote a balance between the vegetative and reproductive growth of plants. Furthermore, this procedure may improve coloring, increase soluble solids, and maintain plant vigor. This study aimed to evaluate the effects of fruit thinning in five varieties of lychee (Bengal, American, Mauritius, Sweet Cliff, and WB4), in the conditions of Jaboticabal - São Paulo state (Brazil). The experimental design was a completely randomized design (CRD) with five treatments and seven replications of three plants each. Treatments consisted of fruit thinning intensities characterized by the number of fruit left on terminal branch panicles, being T1: 3 fruits/branch; T2: 6 fruits /branch; T3: 9 fruit/ branch; T4: 12 fruits/branch; T5: no thinning (control plot). Evaluations were made through a colorimetric assay on ripe fruits, besides a physical and chemical analysis for each variety. The treatments affected the response of varieties on each studied variable. The variety “Mauritius” showed interesting physical and chemical characteristics for the consumer market.

Early blight (caused by Alternaria tomatophila ) is a major disease of tomato with no resistant cultivars. Thus, it is necessary to identify sources of resistance and productive genotypes for the development of new cultivars. Therefore, this study aimed to evaluate the productive potential of cherry tomato genotypes grown in the summer / fall, the severity of early blight on leaves and the incidence of disease in fruits. The treatments consisted of Carolina tomato genotypes, Cereja Vermelho, CH 152 and CLN1561A. The experimental design consisted of randomized blocks with six replications, and the experimental plot had 16 plants. The following characteristics were evaluated: area under the disease progress curve (AUDPC), average number of microinjuries on the fruits (MF), average number of fruits per bunch (NFC), average number of bunches per plant (NCP), average number of fruits per plant (NFP), average yield, number of fruits with incidence of early blight per plant (NFI) and the severity of early blight in leaves (%). The cherry tomato genotype CH152 showed tolerance to early blight with a smaller area under the disease progress curve, lower severity and fruits with incidence of A. tomatophila were not observed in this genotype. The CH152 had the highest number of fruits per bunch, greater number of bunches per plant, higher number of fruits per plant and higher productivity. This line has great potential of being integrated into breeding programs.

Cowpea has great socioeconomic importance in the northeastern part of Pará state. However, in order to provide suitable irrigation management during the dry period this region requires solid information regarding water demand by regional crops. This research aims to determine the water demand, the crop coefficient (Kc) and the uncoupling factor during the different development stages of cowpea in the northeast of Pará. The crop evapotranspiration (ETc) was measured by drainage lysimeters. This information was coupled to the reference evapotranspiration (ETo) to obtain the crop coefficients, which were used to adjust the model function of accumulated degree-days and the leaf area index (LAI). The uncoupling factor was estimated to indicate the factors that control evapotranspiration. The ETc values reached a cumulative total of 267.73 mm ± 10.21 mm during the cowpea cycle. The average value of the uncoupling factor was 0.66. This indicates that the cowpea crop does not fully uncouple from the atmosphere underneath the climatic conditions in northeast Pará. The cowpea Kc values presented averages of 0.8, 1.4 and 0.8 in the vegetative phase, reproductive phase and final stage, respectively. The Gaussian model showed an excellent fit for the estimation of Kc values based on accumulated degree days and the LAI. These amounts differ from others found in the literature. Therefore, it reinforces the necessity for an assessment of crop coefficients under local conditions and for the employment of more precise methods.

Water deficit at certain cotton growth stages can cause severe damage to crop development, affecting physiological processes and reducing reproductive structures, with consequent yield losses. The objective of this study was to evaluate the response of cotton cultivars under water deficit applied at different stages of the crop cycle. We compared the number of bolls per meter, cotton yield, and water use efficiency for eight different cotton cultivars under a water deficit of 15 days. We selected the following growth stages: Emergence (EM), First Square (FS), First Flower (FL), Peak Bloom (PB), and First Open Boll (FOB). The control treatment was irrigated with 100% ETc. The experiment was conducted in Apodi, RN State of Brazil, semiarid region, using a sprinkler irrigation system. The number of bolls per meter, cotton yield, and water use efficiency were influenced by the interaction of cultivars x deficit periods. Lowest values were observed for water suppression in the FL and PB stages. When the water deficit was imposed in the initial stages of growth (EM to FS) or after the FOB stage, the cotton yield reduction was not significant. At the same stage and water deficit, the behavior of the different cultivars was similar. Producers are urged to take this information into account when developing irrigation schemes for cotton crops, thereby avoiding water deficits during the most critical periods of the crop cycle.

Information on the recovering of areas of gravel extraction of the Caatinga biome are scarce. Thus, the objective of this work was to assess the soil fauna as bioindicator of soil quality, evaluating areas with addition of topsoil (WAT) and control areas (CWT) without the addition of topsoil used for forest plantations, which were implemented for recovering gravel extraction areas. A native forest of the Caatinga biome (NFC) was taken as a reference. Ten traps with three replicates were installed in each area, which were evaluated in a randomized block design in split - plot arrangement at the end of the rainy season of different years, 0, 1, 3 and 6 years after the experiment implementation. A total of 45,740 specimens were captured. These specimens were from 36 taxonomic groups. The Acari, Diptera, Entomobryomorpha, Formicidae, Poduromorpha and Symphypleona were the predominant groups in all areas (WAT, CWT and NFC). Nine groups (25% of the total) had restricted occurrence. The fauna richness and diversity were higher in the NFC, followed by the WAT and CWT. The uniformity and total abundance of the soil fauna community showed no defined patterns. The abundance of most groups was inhibited in the treatments evaluated, compared with NFC, however, this adverse effect was more significant in CWT compared with WAT. The CWT and WAT had high similarity and both had very low similarity with NFC. The ecological complexity of soil fauna community was higher in NFC. The soil fauna was efficient as a bioindicator of soil quality, which was higher in WAT, compared with CWT.

The mombin tree (Spondias mombin L.) is found in almost all regions of Brazil. Fresh and processed mombin fruits are increasingly demanded by the market. The objective of this work was to evaluate the post-harvest characteristics of mombin fruits coated with cassava starch and PVC film. Fruits from the mombin cultivar Lagoa-Redonda were harvested at physiological maturity in Limoeiro do Norte, State of Ceará, transported to the Chemistry Laboratory of the Ceará Federal Institute, Limoeiro do Norte campus, and stored for 8 days at 29.7°C and 59% of relative humidity. A completely randomized experimental design in a 3x5 factorial arrangement was used, with three coating types (control, cassava starch at 3%, and cassava starch at 3% combined with PVC film) and five storage times (0, 2, 4, 6 and 8 days), four replicates and five fruits per plot. The fruit skin color, external appearance, soluble solids (SS), titratable acidity (TA), SS/TA ratio and weight loss were evaluated. The PVC film was effective in maintaining the fruit external appearance and decreasing weight loss. The use of cassava starch was not as efficient as the PVC film for conserving mombin fruits. The post-harvest life of fruits was 8 days for those treated with cassava starch or cassava starch combined with PVC film, and 6 days for the control.

This study aimed to evaluate the use of starch degradation index (SDI) in the diagnosis of areas of impact injuries in 'Tommy Atkins' mango, in different maturation stages. The experiment layout was a fully randomized factorial design (5 x 2), represented by five maturation stages and two handlings, with and without impact, with four replicates. SDI was determined through a subjective scale of scores indicating mango pulp darkened areas by reaction with iodine-potassium iodide solution. Subsequently, these scores were correlated with physicochemical quality variables. The results showed no influence of impact on fruit quality, in any of the studied maturation stages. Moreover, soluble solid contents increased throughout maturation stages, regardless of whether the fruits suffered impact or not. As a result, SDI is unsuitable to indicate fruit impact injury. However, there is a good correlation between SDI and pulp color, vitamin C, pH, titratable acidity, soluble solids, SS/ TA ratio and non-reducing sugars.

RESUMO Alterações no espaçamento de semeadura podem gerar modificações no comportamento da cultura, das plantas daninhas e nas relações de competição entre ambas. Um experimento foi desenvolvido para determinar os períodos de convivência e controle das plantas daninhas no algodoeiro, semeado em espaçamento de 0,76 m entre linhas. A semeadura do cultivar FM 993 foi realizada no dia 08/01/2010 buscando-se atingir uma densidade de 190 mil sementes ha-1. Para determinar os períodos de convivência, período anterior a interferência (PAI), período total de prevenção da interferência (PTPI) e período crítico de prevenção à interferência (PCPI), foram analisados os períodos de 0; 5; 10; 15; 22; 29; 36; 43; 50; 57; 64; 71 e 190 dias de convivência ou de controle inicial das plantas daninhas. As plantas daninhas de maior importância relativa foram Amaranthus retroflexus, Bidens pilosa, Eleusine indica, Digitaria horizontalis, Alternanthera tenella e Commelina benghalensis. Admitindo-se a perda máxima de 5% em relação a produtividade, o PAI foi de 11 dias após a emergência após a emergência (DAE), o PTPI foi de 46 DAE e o PCPI de 35 dias, entre 11 e 46 DAE. A tolerância equivalente ao desvio padrão da média do tratamento no limpo resultou no PAI de 6 DAE, PTPI de 55 DAE e PCPI com duração de 49 dias, entre 6 e 55 DAE. | ABSTRACT Changes in row spacing may result in changes in crop and weed behavior and crop-weed competition. A study was performed to determine the periods of weed presence and weed control in cotton sown with 0.76 m spacing between planting rows. Cotton cultivar FM 993 was sown on 01/08/2010 with the aim of reaching a density of 190,000 seeds ha-1. Treatments with either weed presence or weed control during the first 0, 5, 10, 15, 22, 29, 36, 43, 50, 57, 64, 71, and 190 days of cultivation were established to determine the period prior to weed interference (PPI), total period of interference prevention (TPIP) and critical period of weed control (CPWC). The weed species with high relative importance were Amaranthus retroflexus, Bidens pilosa, Eleusine indica, Digitaria horizontalis, Alternanthera tenella, and Commelina benghalensis. Considering a maximum yield loss of 5%, the PPI was established 11 days after cotton emergence (DAE), the TPWC at 46 DAE, and the CPWC between 11 and 46 DAE, for a total duration of 35 days. Considering a maximum acceptable yield loss equal to the standard deviation for the weed-free treatment, the PPI was established at 6 DAE, the TPWC at 55 DAE, and the CPWC between 6 and 55 DAE for a total duration of 49 days