-The insect Dysmicoccus brevipes (Hemiptera: Pseudococcidae) has been reported as an important pest for several crops, especially coffee. The citrus essential oils can be obtained as by-products of the citrus-processing industry and have been tested as an alternative to control different insect groups. Therefore, the objective of this work was to determine the chemical composition and evaluate the toxicity of commercial sweet orange (Citrus sinensis), bitter orange (Citrus aurantium) and Sicilian lemon (Citrus limon) essential oils and pure monoterpene D-limonene on D. brevipes. The essential oils were analyzed by gas chromatography. Two bioassays were conducted; the first assessing the insect mortality in all oils and the second assessing the lethal concentrations (LC 50 and LC 95 ) of the most effective oils. The main components of the oils were D-limonene (83.33%) and Linalool (8.91%) (sweet orange); D-limonene (78.53%) and γ-terpinene (12.65%) (bitter orange); D-limonene (59.78%), beta-pinene (14.71%) and γ-terpinene (10.19%) (Sicilian lemon) and the compound D-limonene had 97% of purity. The highest mortalities were found with the use of the Sicilian lemon (98.68%) and sweet orange (94.11%)oils. The sweet orange oil presented lethal concentrations at 2.21% (LC 50 ) and 3.55% (LC 95 ), and the Sicilian lemon oil at 0.72% (LC 50 ) and 2.91% (LC 95 ). The main component of the sweet orange and Sicilian lemon essential oils was the D-limonene, and the Sicilian lemon oil was most effective oil to control D. brevipes. Keywords:Cochineal. Mortality. Natural products. CARACTERIZAÇÃO QUÍMICA E TOXICIDADE DE ÓLEOS ESSENCIAIS CÍTRICOS SOBRE
The coffee berry borer (CBB), Hypothenemus hampei (Ferrari, 1867) (Coleoptera: Curculionidae: Scolytinae) is one of the main pests of world coffee growing. For the purpose of monitoring the presence of this insect, colored traps and attractives have been developed. Then, the objective of this work was to determine the association between trap colors and ethanol: methanol proportions in the CBB catch, and also to determine the infestation in the coffee plantation by the H. hampei. Painted traps of red, green and colorful (red upper half + green lower half) and six volatile mixtures were used. The reference mixtures consisted of ethanol: methanol (E:M), in the proportions of 1:1 and 1:3, with addition of 0.002 and 0.004 kg of pure caffeine powder. The infestation in the coffee plantation was determined by the H. hampei number count into the fruits and the traps. The insects caught number showed significant interaction between the factors color and mixtures of volatile compounds (F 107:85 = 2.46; p < 0.05). The peaks of H. hampei infestation occurred in the stages of grain formation (January) and maturation (April). The red traps with attractive E:M 1:1 + Benzoic Acid had the most significant effects in the H. hampei catch.
The present study about the oviposition preference of the diamondback moth, <em>Plutella xylostella</em> (Linnaeus, 1758) (Lepidoptera: Plutellidae), can contribute to the determination of the location and time of release of parasitoids and predators or application of insecticides or bio-insecticides in the cabbage culture, <em>Brassica oleracea</em> Capitata group (Linnaeus, 1758) (Brassicales: Brassicaceae). Thus, aimed to this study was to determine the oviposition pattern of diamondback moth on three leaves locations and age of cabbage plants. The locations of the evaluated leaves were external, intermediate and internal. The evaluated plant ages were 20, 40, 60 and 80 days after transplanting. The eggs deposition behavior by diamondback moth was influenced by the development stage of the cabbage plant <em>F</em><sub>6, 96</sub> = 438.21; <em>p</em> = 0.05). The oviposition preference on the external leaves occurred on plants with 20 days old, on the intermediate leaves at 40 days and on the internal leaves at 60 and 80 days. The age with greater oviposition was at 40 days on the external and intermediate leaves; and at 60 days on the internal leaves. Therefore, the behavior of egg deposition of the diamondback moth was altered as the cabbage plant development.
The objective of this study was to evaluate the biological characteristics of Trichogramma pretiosum (Riley 1879) under room temperature and temperature stress by successive generations. The evaluation was carried out in split-plot in the time. The temperature (25 ºC – room temperature and 33 ºC – temperature stress) was the Factor 1 and the Generations (n = 15) were the Factor 2. The biological characteristics evaluated were: longevity; posterior tibia length; number of parasitized eggs; emergence; egg-adult period; sexual ratio and deformed individuals. The increase in temperature, from the first generations of T pretiosum, caused an influence in all observed variables. However, for the emergence and sex ratio variables, there was no significant difference between heat stress and control (room temperature) as of the 14th generation, which suggests an adaptability of the species. This adaptability may imply obtaining more aggressive natural enemies in relation to their host (insect pest) and consequently in the greater efficiency of biological control.
The tomato is a crop of great importance for Brazilian agriculture. Among the most damaging pests, the small tomato borer, Neoleucinodes elegantalis Guenée (Lepidoptera: Crambiadae) has caused great losses, since they directly reach the fruits to be commercialized, being used for its handling a large volume of insecticides. In this way, the use of alternative techniques that help in the management of this pest becomes of great importance. Among them, the use of the egg parasitoid Trichogramma spp. has been promising. Thus, the present study aimed to evaluate the performance of Trichogramma species and/or strains in N. elegantalis by selection of strains. The selection was made based on four lineages maintained in the Nucleus of Scientific and Technological Development in Phytosanitary Management of Pests (NUDEMAFI), being three strains of the species T. pretiosum and one of T. galloi species. The parameters evaluated were percentage of parasitized eggs, egg viability, number of individuals per eggs, sex ratio and number of Trichogramma spp. to be released. The T. galloi (T. g1) showed the best parameters for selection of the strain. Estimating the optimal number of T. g1 in eggs of small-fruit-borer was 82 individuals per egg parasitoid. Therefore, this strain was selected for the management of the small tomato-borer, whose eggs presented favorable physicochemical characteristics for the development of the parasitoid.
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