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Seasonal occurrence of Piezodorus guildinii on different plants including morphological and physiological changes

Zerbino, Maria S., Altier, Nora A., Panizzi, Antônio R.
Journal of pest science 2015 v.88 no.3 pp. 495-505
Eucalyptus, Ligustrum lucidum, Lotus corniculatus, Medicago sativa, Phyllostachys, Piezodorus guildinii, Pittosporum, Trifolium pratense, adults, alfalfa, autumn, bamboos, body size, color, diapause, females, forage legumes, host plants, leaves, lipid content, lipids, morphometry, niches, nymphs, overwintering, pest management, pests, plant litter, sampling, shrubs, soybeans, spring, surveys, winter
Piezodorus guildinii (Westwood) is an important soybean pest in the Americas. Current knowledge about its ecology is limited. To implement holistic and sustainable pest management programs, it is necessary to understand how biotic and abiotic factors regulate its population. Seasonal occurrence on different host plants, and morphological (body morphometry and color) and physiological (lipid content and development of reproductive organs) changes in adults, were studied. Weekly samples were conducted during 2 years on Medicago sativa, Trifolium pratense, Lotus corniculatus (Leguminosae), Pittosporum undulatum (Pittosporaceae), Ligustrum lucidum (Oleaceae), Phyllostachys sp. (Poaceae), and in leaf litter of Eucalyptus sp. (Myrtaceae) at the survey sites (between 33°55′ and 34°17′S). On forage legumes, both nymphs and adults were intercepted, whereas on shrubs, bamboo, and in eucalyptus litter only adults were captured. Alfalfa was the forage legume on which adults were collected during almost the entire year. In this plant species, the abundance of adults and nymphs were higher in comparison with the other plants species and overwintering niches. From the beginning of autumn to the beginning of spring, adults were observed on the foliage of shrubs and bamboo. During autumn and winter, adults were observed underneath eucalyptus litter. In autumn and winter, adults had accumulated lipids reserves, showed undeveloped reproductive organs, smaller body size, and females showed clear coloration of the pronotum band and of the connexivum, indicating reproductive diapause. Results suggest that the control of P. guildinii during spring on alfalfa may reduce the population of bugs before they colonize soybean.