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The present study was developed to evaluate the resistance of the following genotypes of Citrus and related genera to this pest: 'Pera,' 'Natal', and 'Washington Navel' oranges (Citrus sinensis), 'Marsh Seedless' grapefruit (Citrus paradisi), hardy orange 'Rubidoux' (Poncirus trifoliata), kumquat (Fortunella margarita Swingle), citrumelo 'Swingle' (C. paradisi x P. trifoliata), and citrange 'Troyer' (P. trifoliata x C. sinensis). The experiments were performed in greenhouses with plants grafted onto 'Rangpur' lime (Citrus limonia) and placed individually in voile cages. The preference for oviposition in a no-choice test, and the effect of genotype were evaluated. The egg-adult cycle was monitored to determine the effect of genotype on the biology of the insect. Poncirus 'Rubidoux' was the least preferred genotype for oviposition; reduced number of eggs was also found to occur on citrange 'Troyer', and 'Marsh Seedless' was the genotype with the most eggs. No significant variation in the duration of the embryonic period was observed; however, a difference in the viability of eggs was found, with the lowest egg viabilities on 'Swingle.' Kumquat and 'Marsh Seedless' genotypes were correlated with increased durations of the nymphal phase, however, there was no difference in the survival of this phase. Fecundity of females on 'Troyer', 'Swingle', and kumquat was reduced. Considering all of the evaluated parameters, it was concluded that cultivars of sweet orange are the most susceptible genotypes to Diaphorina citri. Regarding oviposition, P. trifoliata 'Rubidoux' showed resistance of the antixenosis type.

RESUMODevido a sua ampla distribuição e aos danos acarretados, Enneothrips flavens Moulton destacase como a principal praga do amendoim no Brasil. O objetivo do presente trabalho foi avaliar, em condições de campo, o comportamento de quatro cultivares de amendoim de hábito de crescimento rasteiro sob infestação natural de E. flavens. ABSTRACT EVALUATION OF PEANUT CULTIVARS WITH RUNNER GROWING HABIT FOR RESISTANCE TO ENNEOTHRIPS FLAVENS, MOULTON (THYSANOPTERA: THRIPIDAE). Due to its widespread distribution and known damages, Enneothrips flavensMoulton is considered the major pest of the peanut crop in Brazil. The objective of the present study was to evaluate the behavior of four runner peanut cultivars under natural field infestation of this insect. The experiments were carried out in the experimental area of FCAV/UNESP, Jaboticabal, state of São Paulo, Brazil, using a completely randomized block design with 4 treatments and 6 replications. The cultivars studied were IAC Caiapó, IAC 125, IAC 147 and Runner IAC 886. Insect infestation and damage, as well as plant behavior were evaluated as to the number of nymphae and adults, percentage of attacked leaflets, symptoms of attack intensity, number of apical buds/plant, plant dry weight, yield of unshelled pods/plant and 100 kernel weight. No significant difference was noted between cultivars regarding the level of E. flavens (adult and nymphae) infestation. The largest nymphae infestation was recorded at the 15-41 DAE (days after emergency) period. As for the adults, the largest infestation occurred between 15 and 48 days after emergence. The evaluation of yield performance under thrips (E. flavens) infestation suggested that the cultivar IAC Caiapó behaved as tolerant to the attack of this insect.

Ingestion of proteinase inhibitors leads to hyperproduction of digestive proteinases, limiting the bioavailability of essential amino acids for protein synthesis, which affects insect growth and development. However, the effects of proteinase inhibitors on digestive enzymes can lead to an adaptive response by the insect. In here, we assessed the biochemical response of midgut proteinases from the eucalypt defoliator Thyrinteina arnobia (Stoll) to different concentrations of berenil, a bis-benzamidine proteinase inhibitor, on eucalyptus. Eucalyptus leaves were immersed in berenil solutions at different concentrations and fed to larvae of T. arnobia. Mortality was assessed daily. The proteolytic activity in the midgut of T. arnobia was assessed after feeding on plants sprayed with aqueous solutions of berenil, fed to fifth instars of T. arnobia for 48 h before midgut removal for enzymatic assays. Larvae of T. arnobia were able to overcome the effects of the lowest berenil concentrations by increasing their trypsin-like activity, but not as berenil concentration increased, despite the fact that the highest berenil concentration resulted in overproduction of trypsin-like proteinases. Berenil also prevented the increase of the cysteine proteinases activity in response to trypsin inhibition.

The silverleaf whitefly Bemisia tabaci biotype B is one of the most harmful insect pests for agricultural and vegetable crops. Beside the direct damage, it transmits pathogenic virus and induces plant physiological disorders, such as the squash silverleaf disorder. In this research we evaluated the development of leaf silvering in squash cultivars submitted to artificial infestation of B. tabaci biotype B. An experiment was conducted under field conditions, in Campinas, São Paulo State, Brazil, during the season [2003][2004]. The germplasm (Cucurbita spp.) comprised of seven cultivars of summer squash and nine of bush squash. The experiment used a complete randomized blocks design, with 16 treatments (cultivars) and five replications. Each plot consisted of two plants. The artificial infestation was done when the plants emitted the third pair of leaves, by transplanting soybean plants infested with silverleaf whitefly between the squash plots. The leaf silvering was evaluated every two or three days, using a rating scale varying from 1 (no symptom) to 5 (leaves completely silvered). The highest level (5.0) was observed in 'Baianinha', 'Golden Delight', 'Caravela' and 'Arlika', while 'novita' (2.5), 'Atlas' (2.0) and 'Atlanta AG-303' (1.5) showed light symptoms, indicating that these have low sensibility to this physiological disorder.

Popula on Gene c Structure of Bemisia tabaci (Hemiptera: Aleyrodidae) U lizing Microsatellite Markers

ABSTRACT. The silverleaf whitefly, Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae), is a cryptic species complex that contains some of the most damaging pests in tropical and subtropical regions. Recent studies have indicated that this complex is composed of at least 24 distinct and morphologically indistinguishable species that mainly differ in their ability to transmit phytoviruses, adapt to hosts, and induce physiological changes in certain hosts. The importance of this species has been increasing worldwide, because it serves as a phytovirus vector, particularly for geminiviruses, in economically important crops. Here, we aimed to examine the population variability (2013) G.E. do Valle et al.-soybean], UBman [Ubatuba (SP, Brazil) -cassava], and PEmel [Petrolina (PE, Brazil) -melon]. Thirteen polymorphic loci with 50 alleles were observed, with an average of 2.37 (range: 2.00-2.91) alleles per population. The UBman and PEmel B. tabaci populations were the most differentiated, which was probably caused by insect adaptation to the host plant and the use of insecticides. A 33.87% interpopulation variation was observed, indicating that microsatellites may be used to measure differentiation among these B. tabaci populations. Based on the comparison of microsatellites in the current study, only the Middle East-Asia Minor 1 population of B. tabaci was found in the six populations.

Red spider mite (Tetranychus evansi) is considered one of the main tomato pests in Africa. As an alternative to chemical control, the use of pest-resistant cultivars has been considered a desirable and environment-friendly choice. Therefore, our study aimed to evaluate the influence of trichomes on settlement and oviposition preferences of T. evansi in African tomato varieties, besides comparing them to South American wild tomato species. First, free- and no-choice laboratory tests were carried out to investigate settlement and oviposition preferences of females on leaflets of two South American wild tomato species (Solanum pennellii LA-716 and S. habrochaites var. hirsutum PI134417) and five  African tomato varieties (S. lycopersicum cv. Kekefo, Akikon, TLCV15, Tounvi, and TOML4), the latter are widely grown in Benin. Thereafter, leaf trichome types were determined and densities were estimated and then correlated to numbers of settled females and laid eggs on leaflets of each assessed genotype. According to our findings, females strongly preferred to settle and oviposit on African varieties rather than on South American genotypes. Regarding trichome density, non-glandular type Va showed significant positive correlations with both studied parameters, with the highest amounts in African genotypes. Conversely, glandular trichome density (mainly types I, IV, and VI) presented significant negative correlations with preference indicators, with the largest densities in South American species. The high density of non-glandular trichomes on leaflets of the varieties Akikon, Tounvi, Kekefo, TOML4, and TLCV15 might have been one of the causes of preference of T. evansi females.