Effects of Temperature and Relative Humidity on the Embryonic Development of Hypera postica Gyllenhal (Col.: Curculionidae)

The combined effect of the temperature and relative humidity on the survival and development time of the eggs of Spanish populations of the weevil Hypera postica, a key pest of alfalfa around the world, was evaluated under laboratory conditions. The experimental temperatures ranged from 8 to 36 °C, in 4 °C increments. Three relative humidity ranges were defined: high, medium, and low. Eggs of the alfalfa weevil successfully developed until larval emergence at all of the 24 conditions tested. However, the temperature and relative humidity affected the survival of the eggs. The egg developmental time decreased as the temperature increased from 8 to 32 °C, and the longest time was recorded at a low relative humidity (RH). The relationship between the development rate and temperature fit well to the lineal model for relative humidity. The minimum development threshold (T0) and the thermal requirement for egg development (K) ranged between 3 and 4 °C and 209 and 246 degree-days, respectively. According to these values and the occurrence of eggs and larvae (in winter) and adults (in autumn) in field samplings, the period of oviposition was determined. The results of the study contribute to better understanding the annual cycle and phenology of H. postica in the Iberian Peninsula and southern Europe.

Reproductive Biology and Evidence of Diapause in the Cowpea Curculio (Coleoptera: Curculionidae)

Chalcodermus aeneus Boheman (Coleoptera: Curculionidae) has been the most destructive insect pest of black-eyed peas or cowpeas, Vigna unguiculata L. (Fabales: Fabaceae), over the last century in the southeastern United States. The historical distribution of this semitropical pest suggests the likelihood that diapause plays a key role in the overwintering success in parts of the United States. However, this report is the first to document biological evidence for diapause in C. aeneus. Our study assessed larval emergence from cowpea pods in the summer to fall growing seasons, egg development in female adults over the first (summer) and second (fall) generations, and adult emergence from infested soil after the first and second generations. There was a clear reduction in larval emergence from summer to fall. Egg and follicle development in female C. aeneus dropped off dramatically by September of each year. There was an extended emergence pattern of weevil adults from the soil in the fall as compared to the summer generation. Any future regional management of cowpea curculio will have to take into account the ability of this insect to diapause, thereby increasing its capacity to overwinter in regions where the cowpea crop, a warm-season, semitropical plant, is terminated with winter freezing temperatures.

A Survey of Mosquito Species in Public Schools of Metro Manila, Philippines Using Ovitraps as Surveillance Tool

Objective. This study assessed the species composition of mosquitoes collected from ovitraps in selected public schools of Metro Manila, Philippines. Materials and Methods. Ovitraps were installed from November 2013 to February 2014, in purposively selected public elementary and high schools of Metro Manila. Ovitraps were installed inside classrooms and collected weekly and examined for mosquito eggs and larvae. Speciation was done once a month from November 2013 to February 2014. All positive paddles were immersed in water for larval emergence, reared to fourth instars and were identified using taxonomic keys. Results. A total of 1,482 ovitraps were installed in the selected public schools, and 18,325 larvae were collected from elementary schools, while 16,670 larvae were collected from high schools.The mean ovitrap index or infestation rate was 49.69% during the period of data collection. Mosquito larvae were identified as Aedes aegypti (88.94%) and Aedes albopictus (11.06%). Aedes aegypti and Aedes albopictus coexisted in some of the examined paddles. No significant differences were observed between the type of school and the presence of Aedes larvae. Significant differences were observed between total number of mosquito larvae and months of collection. Conclusion. The presence of Aedes mosquitoes in schools evidently shows that continuous vector surveillance in schools is necessary as this information will help in the formulation of proactive vector control activities, thereby preventing the occurrence of mosquito-borne diseases.

Control of the South American fruit fly in pear with natural-based products

This study aimed to assess, in laboratory conditions, the effect of andiroba oil (2L 100L-1), kaolin (7.5Kg 100L-1), azadirachtin (2.5L 100L-1), metidationa (100mL 100L-1) and distilled water (control) on the oviposition and mortality of adults of A.fraterculus in no-choice and free-choice tests. The experimental design was randomized with five treatments and 20 replicatesfor the no-choice test; and 15 replicates for the free-choice test. Fruits were immersed in each treatment solution, dried at room temperature and placed in pots with two couples of A. fraterculus (no-choice test) and in arenas with four couples along with a fruit that was previously immersed in water (free-choice test).Twenty-five days after infestation, fruits were dissecated and the number of larvae was recorded as well the number of pupae and adults. Only methidathion was effective on adults with mortality of 91.3% (P<0.05). There was no larval emergence and, consequently, pupae and adult development in fruits treated with andiroba oil and methidathion in both tests. Azadirachtin and kaolin did not present any effect on A. fraterculus. Andiroba oil was effective on the reduction of the infestation of pear fruits by A. fraterculus.

Cryptocephaline Egg Case Provides Incomplete Protection from Generalist Predators (Coleoptera: Chrysomelidae)

The egg case ofCryptocephalus rufipes(Goeze) is described and illustrated. In laboratory trials, eggs of field-collectedC. rufipeswere observed for larval emergence (untreated control) or exposed to two species of generalist predators,Chrysoperla carnea(Stephens) orXylocoris flavipes(Reuter) in no-choice experiments. The behaviour of the predators upon contact with theC. rufipeseggs was observed. The number of hatching larvae was counted and compared. In the presence of each of the two species of predators, larval emergence was significantly reduced. Eggs that were not protected by an egg case were completely consumed by the predators.C. rufipeseggs were therefore incompletely protected from the studied generalist predators. This is the first study showing experimentally the protective function of cryptocephaline egg case.

Gamma Radiation Sensitivity of Different Stages of Saw-Toothed Grain Beetle Oryzaephilus Surinamensis L. (Coleoptera: Silvanidae)

Gamma Radiation Sensitivity of Different Stages of Saw-Toothed Grain BeetleOryzaephilus SurinamensisL. (Coleoptera: Silvanidae)The effect of gamma irradiation on different developmental stages ofOryzaephilus surinamensisL., was investigated. Results showed that a required dose to prevent larval emergence from irradiated 1-2-days-old eggs was 60 Gray (Gy), and 350 Gy was required to prevent adult emergence from 15-days-old larvae. Also the required dose of radiation to prevent adult emergence from irradiated 5-days-old pupa was 700 Gy. The dose of 200 Gy caused 100% mortality of irradiated adults 28 days after treatment. In addition, the effect of gamma rays was studied on the developmental stage period of each irradiated stage till adult emergence. The results revealed that there was a dose-dependent increase of the developmental periods. The growth index of adults was significantly decreased with increasing dose of radiation administered to eggs, larvae and pupae. It is recommended that doses between 600 and 700 Gy should be used to control population growth ofO. surinamensiswhen targeting pupae and adults present in stored products.