Overwintering of Piezodorus guildinii (Heteroptera, Pentatomidae) Populations.

Piezodorus guildinii (Westwood) is a soybean pest that causes significant economic losses in the Americas. The variability of overwintering (diapause) traits was evaluated in populations of the Southwest (SW) (33°55'-34°17'S, 57°13'-57°46'W) during 2-year period (2011-2013) and of the Northwest (NW) (32°01'-33°02'S, 57°50'-57°24'W) during 1-year period (2014-2015) Regions of Uruguay. Samples were taken from different plant species (cultivated legumes, wild shrubs, and trees) and from overwintering sites (leaf litter and bark). Alfalfa, Medicago sativa L. was the main host, with a collection period of 10-11 months in the SW and 12 months in the NW. Cluster analysis for each sex was carried out to group the months according to the similarity in diapause traits of populations (body size, body lipid content, immature reproductive organs, and clear type of pronotum band and connexivum in females). Female diapause in the SW was longer (beginning of autumn to end of winter) than that in the NW (mid-autumn to mid-winter). Male diapause was longer (mid-autumn to mid-winter) in SW1 (1st year) than in SW2 (2nd year) and NW (late-autumn to mid-winter). In both regions, male diapause was shorter than female. Differences were associated with maximum temperature at daylight hours ≤ 12.1, being necessary maximum temperatures below 23.8 °C for females and 19.2 °C for males to initiate diapause.

Performance of Nymph and Adult of Piezodorus guildinii (Westwood) (Hemiptera: Pentatomidae) Feeding on Cultivated Legumes.

Performance of nymphs and adults of Piezodorus guildinii (Westwood) feeding on different cultivated legumes was studied under controlled laboratory conditions (25 ± 1°C, 80 ± 10% RH, 14 h of photophase) on soybean immature pod (SIP; R5.5-R6), birdsfoot trefoil immature pod (BTIP), alfalfa immature pod (AIP), and red clover flower with immature seeds (RCF). Food had significant effects on the life history of P. guildinii. The major differences in nymph survivorship were observed at second and third instars, with similar survivorship on SIP and AIP as hosts and higher than that recorded on BTIP and RCF. Total nymph mortality was much greater on BTIP (87.6%) than on SIP (32.6%) and AIP (54.2%); all nymphs died on RCF. Food did not affect nymph development time (about 20 days). Adult longevity was highest and lowest on AIP and RCF (62 and 32 days), respectively. Percentage of ovipositing females was highest (≈ 80%) on SIP and AIP, and intermediate on BTIP (52.2%); no females reproduced on RCF. Fecundity on SIP and AIP was similar (≈ 9 egg masses/female; and ≈ 141 eggs/female) and twice as higher than on BTIP (4.1 egg masses/female; and 60.2 eggs/female). Egg fertility (58%) did not vary with food sources. Adults fed on SIP and AIP gained weight during 43 days, remained unaltered on BTIP, and decreased on RCF. Data obtained indicated that SIP and AIP are suitable food sources, and emphasize the importance of alfalfa as a host plant of P. guildinii in Uruguay.

Volume de calda e inseticidas no controle de Piezodorus guildinii (Westwood) na cultura da soja / Diferent spray volumes and insecticides in the control of Piezodorus guildinii (Westwood) in soybean crop

Em pulverizações com bicos hidráulicos, o volume de calda é um dos aspectos mais importantes para o sucesso do controle químico de pragas. O objetivo deste trabalho foi avaliar o efeito do volume de calda e inseticidas no controle de Piezodorus guildinii (Westwood), na cultura da soja. Testaram-se os volumes de calda de 50, 100 e 150l ha-1 e os inseticidas endossulfam (437,5g i.a. ha-1) e tiametoxam + lambda-cialotrina (21,15 + 15,90g i.a. ha-1). Tiametoxam + lambda-cialotrina apresentou maior efeito residual e controle de P. guildinii em relação à endossulfam. Esses inseticidas respondem da mesma forma, aumentando a eficiência de controle da praga com o aumento do volume de calda.

The spray volume is one of the most important aspects interfering on the success of pest control. The objective of this study was to evaluate the effects of spray volume on the efficiency of the insecticides in the control of Piezodorus guildinii (Westwood) in soybean crop. Were evaluated the volumes of 50, 100 and 150l ha-1 and the insecticides endosulfan (437.5g a.i. ha-1) and tiametoxan + lambda-cyhalothrin (21.15 + 15.90g a.i. ha-1). Tiametoxan + lambda-cyhalothrin had better residual and control of P. guildinii than endosulfan. Both insecticides showed the same behavior, increasing P. guildinii control with spray volume increasing.

Volume de calda e inseticidas no controle de Piezodorus guildinii (Westwood) na cultura da soja

The spray volume is one of the most important aspects interfering on the success of pest control. The objective of this study was to evaluate the effects of spray volume on the efficiency of the insecticides in the control of Piezodorus guildinii (Westwood) in soybean crop. Were evaluated the volumes of 50, 100 and 150l ha-1 and the insecticides endosulfan (437.5g a.i. ha-1) and tiametoxan + lambda-cyhalothrin (21.15 + 15.90g a.i. ha-1). Tiametoxan + lambda-cyhalothrin had better residual and control of P. guildinii than endosulfan. Both insecticides showed the same behavior, increasing P. guildinii control with spray volume increasing.

Em pulverizações com bicos hidráulicos, o volume de calda é um dos aspectos mais importantes para o sucesso do controle químico de pragas. O objetivo deste trabalho foi avaliar o efeito do volume de calda e inseticidas no controle de Piezodorus guildinii (Westwood), na cultura da soja. Testaram-se os volumes de calda de 50, 100 e 150l ha-1 e os inseticidas endossulfam (437,5g i.a. ha-1) e tiametoxam + lambda-cialotrina (21,15 + 15,90g i.a. ha-1). Tiametoxam + lambda-cialotrina apresentou maior efeito residual e controle de P. guildinii em relação à endossulfam. Esses inseticidas respondem da mesma forma, aumentando a eficiência de controle da praga com o aumento do volume de calda.

Volume de calda e inseticidas no controle de Piezodorus guildinii (Westwood) na cultura da soja

The spray volume is one of the most important aspects interfering on the success of pest control. The objective of this study was to evaluate the effects of spray volume on the efficiency of the insecticides in the control of Piezodorus guildinii (Westwood) in soybean crop. Were evaluated the volumes of 50, 100 and 150l ha-1 and the insecticides endosulfan (437.5g a.i. ha-1) and tiametoxan + lambda-cyhalothrin (21.15 + 15.90g a.i. ha-1). Tiametoxan + lambda-cyhalothrin had better residual and control of P. guildinii than endosulfan. Both insecticides showed the same behavior, increasing P. guildinii control with spray volume increasing.

Em pulverizações com bicos hidráulicos, o volume de calda é um dos aspectos mais importantes para o sucesso do controle químico de pragas. O objetivo deste trabalho foi avaliar o efeito do volume de calda e inseticidas no controle de Piezodorus guildinii (Westwood), na cultura da soja. Testaram-se os volumes de calda de 50, 100 e 150l ha-1 e os inseticidas endossulfam (437,5g i.a. ha-1) e tiametoxam + lambda-cialotrina (21,15 + 15,90g i.a. ha-1). Tiametoxam + lambda-cialotrina apresentou maior efeito residual e controle de P. guildinii em relação à endossulfam. Esses inseticidas respondem da mesma forma, aumentando a eficiência de controle da praga com o aumento do volume de calda.