Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Plant Protection Department, Ctra. La Coruña Km. 7.5, 28040 Madrid, Spain
Dr. Manuel González-Núñez
Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Plant Protection Department, Ctra. La Coruña Km. 7.5, 28040 Madrid, Spain
Baseline susceptibility to the Cry1Ab delta-endotoxin from Bacillus thuringiensis (Berliner) was determined for four populations of Sesamia nonagrioides (Lefebv
The effects of azadirachtin on two pests: neonate larvae and newly emerged adults of Ceratitis capitata (Wiedemann) and last instar larvae of Spodoptera exigua (Hubner); and three natural enemies: newly emerged adults of Opius concolor Szepligeti, second instar larvae of Chrysoperla carnea (Stephens), and fifth instar nymphs of Podisus maculiventris (Say) were studied in laboratory. Adult insects were exposed to a non-oil formulation of azadirachtin (Align, emulsifiable concentrate, 3.2% azadirachtin, Sipcam Inagra, Spain) via their drinking water and immature instars were reared in the presence of the insecticide-treated diet. The natural enemies were exposed to at least the maximum field recommended concentration of the insecticide (0.15% v/v). Azadirachtin was highly toxic to neonate larvae of C. capitata and prevented adult emergence at a concentration of 1 mg a.i. l -1 . When adults were fed the insecticide at the maximum recommended concentration, their survival was not affected but egg laying was totally inhibited. Last instar S. exigua larvae were also very susceptible (LC 50 = 7.7 mg a.i. l -1 ) and at a concentration of 10 mg a.i. l -1 fecundity of surviving adults, and egg fertility, were reduced by 72 and 85%, respectively. Effects on O. concolor were large, and significant reductions in longevity, percentage of attacked hosts, and progeny size per female, were recorded. The predator P. maculiventris was much less sensitive to azadirachtin, but slight reductions in survival of emerged adults and of reproductive parameters occurred. The insecticide had no significant effect on C. carnea larvae fed with treated Sitotroga cerealella (Oliver) eggs, probably because of its inability to penetrate inside the egg.
21 November 2015 in European Journal of Entomology
The poplar lace bug, Monosteira unicostata (Mulsant & Rey), is one of the most important pests of almond trees in the Mediterranean area. The developmental times and survival of the immature stages of this tingid were determined at 16, 19, 22, 25, 28, 31, 34, 35.5, 37 and 39?C, 60 ± 10% relative humidity and under a 16L : 8D photoperiod. At 16 and 39?C, 100% mortality was recorded during immature development, with the egg, first and second nymphal instars the most susceptible. The lowest mortality was recorded at 28?C (9.8%). As temperature increased, the total developmental period decreased and the shortest duration was recorded at 34?C (12.1-12.2 d). At 37?C, the developmental time was slightly longer (12.5-13.0 d). The thermal requirement for complete development, from egg to adult, was 229.2 DD. Several non-linear models were fitted to the developmental rate data recorded for the range of temperatures tested. Selection criteria indicated that the Lactin model best described the relationship between developmental rate and temperature. It predicted lower and upper thermal thresholds for the complete preimaginal period of 14.8 and 39.1?C, respectively. Models were validated by comparing their predictions for the total preimaginal period with the developmental times recorded at three different fluctuating temperature regimes. The Lactin model again best fitted the actual durations recorded. This model could be used in IPM programs for predicting the moment of occurrence of the most damaging generations of this species.