This paper describes the relationship between spectral resolution and classification accuracy in analyses of hyperspectral imaging data acquired from crop leaves. The main scope is to discuss and reduce the risk of model over-fitting. Over-fitting of a classification model occurs when too many and/or irrelevant model terms are included (i.e., a large number of spectral bands), and it may lead to low robustness/repeatability when the classification model is applied to independent validation data. We outline a simple way to quantify the level of model over-fitting by comparing the observed classification accuracies with those obtained from explanatory random data. Hyperspectral imaging data were acquired from two crop-insect pest systems: (1) potato psyllid (Bactericera cockerelli) infestations of individual bell pepper plants (Capsicum annuum) with the acquisition of hyperspectral imaging data under controlled-light conditions (data set 1), and (2) sugarcane borer (Diatraea saccharalis) infestations of individual maize plants (Zea mays) with the acquisition of hyperspectral imaging data from the same plants under two markedly different image-acquisition conditions (data sets 2a and b). For each data set, reflectance data were analyzed based on seven spectral resolutions by dividing 160 spectral bands from 405 to 907 nm into 4, 16, 32, 40, 53, 80, or 160 bands. In the two data sets, similar classification results were obtained with spectral resolutions ranging from 3.1 to 12.6 nm. Thus, the size of the initial input data could be reduced fourfold with only a negligible loss of classification accuracy. In the analysis of data set 1, several validation approaches all demonstrated consistently that insect-induced stress could be accurately detected and that therefore there was little indication of model over-fitting. In the analyses of data set 2, inconsistent validation results were obtained and the observed classification accuracy (81.06%) was only a few percentage points above that obtained using random data (66.7-77.4%). Thus, our analysis highlights a potential risk of model over-fitting and emphasizes the importance of testing for this important aspect as part of developing reliable and robust classification models.

We studied a population of Liriomyza sativae Blanchard (Diptera: Agromyzidae) identified by morphological and molecular techniques from the semiarid region of the Brazilian northeast. The influence of temperature and relative humidity on the survival and reproductive parameters of L. sativae in cowpeas (Vigna unguiculata L. Walp.) (Fabales: Fabaceae) was evaluated. We used temperatures of 18, 20, 22, 25, 28, 30, and 32 +/- 1 degrees C (50 +/- 10% RH) and relative humidity values of 30, 50, 70, and 90 +/- 10% (25 +/- 1 degrees C) under a 14 L:10 D photoperiod. Adult longevity decreased as temperature and relative humidity increased and was greater, in general, for females. The preoviposition and oviposition periods also decreased as temperature increased, whereas relative humidity only caused reductions in the oviposition period at higher levels. Fecundity was similar in the range from 18 to 30 degrees C but decreased at 32 degrees C with respect to relative humidity; the best performances of L. sativae occurred at lower levels. The pattern of oviposition rate changed with temperature and relative humidity. Regardless of temperature and relative humidity, L. sativae laid between 75 and 92% of its eggs on the adaxial surface of the cowpea leaves. This information will be highly useful to design a leafminer production system aimed at the multiplication of natural enemies, as well as for pest management in the field.

-This research aimed to study the infl uence of temperature and relative-humidity (RH) on the development of Liriomyza sativae Blanchard during the egg-adult period, in cowpea, to provide essential information for future biological control projects against the pest. An inverse relation was observed between temperature increase in the range from 15°C to 32°C and development duration. Larval survival was not affected in the temperature range studied, while a high mortality of pupae was observed at 32°C (59.9%). RH did not affect the development time of the immature stages, although it infl uenced their survival. The lower developmental temperature threshold obtained for the egg-adult period was low (7.3°C) when compared with other species of Liriomyza, and was rather low for the larval stage (3.4°C). Based on the thermal requirements for L. sativae, it was possible to estimate the occurrence of 24.5 annual generations at a melon producing region in state of Rio Grande do Norte, Brazil. For laboratory rearing aimed at biological control pest programs, the best rearing conditions are 30°C and 50% RH for the larval stage and 90% RH for the pupal stage.KEY WORDS: Leaf miner, abiotic factor, thermal requirement, biology, molecular characterization RESUMO -A pesquisa teve como objetivo estudar a infl uência da temperatura e da umidade relativa do ar (UR) no desenvolvimento de Liriomyza sativae Blanchard, durante o período ovo-adulto, em feijão caupi, para fornecer subsídios a futuros projetos de controle biológico da praga. Verifi cou-se uma relação inversa entre o aumento da temperatura na faixa de 15°C a 32°C e a duração do desenvolvimento. A sobrevivência larval não foi afetada na faixa térmica estudada, enquanto a 32°C houve alta mortalidade de pupas (59,9%). A UR não afetou a duração dos estágios imaturos, embora tenha infl uenciado a sua sobrevivência. O limiar térmico inferior de desenvolvimento obtido para o período ovo-adulto foi baixo (7,3°C), se comparado a outras espécies de Liriomyza, e bastante reduzido para a fase larval (3,4°C). De acordo com as exigências térmicas constatadas para L. sativae foi possível estimar a ocorrência de 24,5 gerações anuais na região produtora de melão, em Mossoró, RN. Para criações de laboratório, visando à implementação de programas de controle biológico da praga, as melhores condições são temperatura de 30°C e UR de 50% para a fase de larva e 90% para o estágio de pupa de L. sativae.

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The efficacy of 14 different insecticides was tested for the control of onion thrips Thrips tabaci (Lindeman, 1889) on onion in Itajaí Valley, SC during 2018. The insecticides were sprayed six times at intervals of about seven days, we evaluated the number of nymph of thrips per plant 48 hours after spray, visually rated for thrips damage at 96 DAT and total and commercial onion bulb production. Significant diferences were observed between various insecticides evaluated. The treatments formetanate hydrochloride, spinetoram and abamectin proved the best thrips control, less thrips damage and good total and commercial productivity. The insecticide profenofos + cypermethrin exhibited reduction of thrips nymph and better total and comercial production comparing control however not reduced thrips damages. The insecticides thiacloprid, thiamethoxam + lambda-cyhalotrin, and Imidacloprid reduced the thrips density but had similar results for thrips damages and onion bulb production comparing with control, excepting total productivity for the neonicotinoids thiacloprid and and Imidacloprid.

O objetivo deste estudo foi avaliar a incidência e danos de tripes em cebola, em dois sistemas de manejo de solo com plantio direto na palha em sistema orgânico e no convencional com revolvimento, e sua relação com a produtividade. A cultivar de cebola utilizada foi a Epagri 362 Crioula Alto Vale. O estudo foi realizado durante os anos de 2014, 2015, 2016 e 2017. A incidência de tripes na maioria das avaliações foi menor em sistema orgânico com plantio direto na palha e menor densidade de plantas comparado ao convencional. Os danos foliares causados por tripes tenderam a ser similares entre os sistemas. A produtividade não foi correlacionada de maneira negativa com a incidência e danos de tripes. A produtividade foi superior em sistema convencional.

Este trabalho foi realizado com objetivo de avaliar o efeito da poda apical na produção de frutos em pepineiros para conserva. O estudo foi conduzido na Epagri, EEItuporanga/SC, em 2018. O delineamento utilizado foi o de blocos ao acaso com parcelas subdividas com quatro repetições. Os fatores empregados foram condução apical das plantas (sem e com poda) nas parcelas, e seis cultivares (Ajax F1, Amour F1, Antero F1, Calypso, Kybria F1, Marinda F1), nas subparcelas. Os cultivares mais produtivos foram: Kybria F1 e Amour F1, com respectivos 2,6 e 2,5 kg de massa fresca de frutos por planta e 134,2 e 138 frutos por planta, independente da realização da poda apical; Marinda F1 (2,4 kg de massa fresca de frutos por planta e 138,3 frutos por planta) sem poda e Ajax F1 (2 kg de massa fresca de frutos por planta e 108,4 frutos por planta), com poda. Quanto à massa fresca de frutos, os híbridos mais produtivos, Kybria F1, Amour F1, Marinda F1 e Ajax F1, apresentaram menores valores médios de massa, independente do tipo de condução apical, com respectivos 19,2, 18, 17 e 18 g, quando comparada ao Calypso (média plantas podadas: 22,9 g). O rendimento de frutos, cujo valor médio foi de 98,9%, não foi afetado pela poda. Palavras-chave: Cultivo protegido; cultivo sem solo; Cucumis sativus.