Natural infestations of cereal aphids caused significant reductions in grain yield in field plots of early and late cultivars of barley, wheat, and oats in southwestern Quebec. Severely reduced grain yields resulted when caged plants of wheat and late cultivars of barley and oats were artificially infested, but early cultivars of barley and oats were less affected. The percentage protein of grain was significantly reduced in all crops, but wheat and late oats were most affected.

Can. Enr. 112: 609-614 (1980) Samples of the bodies and elytra of Entomoscelis americana Brown were analyzed separately by X-ray energy-dispersive spectroscopy. Discriminant analysis revealed that the chemoprints of the bodies of newly-emerged beetles (1 wk old) were distinct from those of postaestivation beetles (9-to 10-wk old). However, the chemoprints of the elytra of newlyemerged and post-aestivation beetles were not as different as those of the bodies as demonstrated by the overlap in the plot of the first two canonical variables. The variances of the mean difference of individual variables between newly-emerged and post-aestivation groups generally were smaller for elytra than for bodies. This suggests that the chemoprints of the elytra of E. americana are more stable than those of the bodies and consequently the elytra should be more suitable than the bodies in insect dispersal studies utilizing the X-ray energy-dispersive spectroscopy technique. RCsumC On a analyse sipariment des Bchantillons de corps et d'elytres de Entomoscelis americanaBrown par radiospectroscopie i dissipation d'energie. L'analyse discriminante revble que les empreintes chimiques laissees par les corps des coliopteres nouvellement eclos (1 semaine) different de celles des imagos apres diapause estivale (9-10) semaines). Mais les empreintes des Blytres des deux groupes ne different pas autant que celles des corps, comme en temoigne le chevauchement des deux premieres variables canoniques dans la parcelle d'essai. Les variances de la difference moyenne de chaque variable entre les deux groupes sont generalement plus faibles pour les elytres que pour les corps. I1 semblerait donc que les empreintes chimiques des 6lytres de E. americana soient plus stables que celles des corps, de telle sorte que les elytres devraient se prkter davantage aux etudes de dispersion d'inergie par cette technique de radiospectroscopie.

Field and laboratory studies have been carried out on the biology and food preference of Diaphania indica Saund. in PDR of Yemen. The effect of different constant temperatures on the development of the insect has shown that as the temperature increases, egg incubation period, larval and pupal periods decreases considerably. At fluctuating temperatures of 25–35.9 °C, the egg, larval and pupal periods were 3.5, 11.5 and 6.2 d, respectively. Field and laboratory studies have shown that the insect prefers Cucumis melo (sweet melon) than Citrulus vulgaris (water melon) and Cucumis sativa (cucumber). Although the larvae consume more food of C. vulgaris (121.7 mg) than of C. melo (101.6 mg), they produce more faeces when fed on the former. The average larval weight (65.3 mg) of caterpillars fed on C. melo is more than those fed on C. vulgaris (54.3 mg). This shows more assimilation of food from C. melo when compared to C. vulgaris. Zusammenfassung Über die Bionomie des Melonenzünslers Palpita (Diaphania) indica (Saund) (Pyralidae: Lepid.) in der Volksrepublik Yemen Zur Bionomie und Nahrungswahl von Diaphania indica wurden im Yemen Freiland‐ und Laboruntersuchungen durchgeführt. Bei wachsenden Temperaturen zwischen 25 und 36 °C betrugen die Ei‐, Larven‐ und Puppen‐Perioden 3.5, 11.5 und 6.2 d. Als Nahrungspflanze wurde die Süßmelone (Cucumis melo) der Wassermelone (Citrulus vulgaris) und der Gurke (Cucumis sativa) vorgezogen. Obgleich die Raupen mehr C. vulgaris (121.7 mg) als C. melo (101.6 mg) frassen, produzierten sie mehr Kot bei letzterer Nahrung. Das mittlere Gewicht der Raupen nach Fraß an C. melo war mit 65.3 mg höher als nach Fraß an C. vulgaris (54.3 mg). Dies zeigt, daß C. melo in größerem Umfang als C. vulgaris assimiliert wurde.

The Citrus leaf miner, Phyllocnistis citrella is an important pest of citruses in the Sudan and other parts of the world. Studies on its biology have shown that the egg stage took 2 to 6 days to hatch, the average larval (4 instars) and pupal durations were 7–8 and 8–9 days, respectively; while the total life cycle from egg laying to adult emergence took about 18 days (winter time). The insect preferred the lower surface of the leaf for egg laying. On the basis of infested area, number of living larvae and pupae per leaf and length of mines, grapefruit, Citrus paradisi, was found to be the most susceptible citrus species while mandarine C. nobilis was found to be the least susceptible one followed by lime, C. aurantiifolia. Suggested reasons for this preference and susceptibility were given. Zusammenfassung Beiträge zur Biologie und zum Vorkommen der Zitrusminiermotte, Phyllocnistis citrella Staint. (Gracilariidae, Lepid.) im Sudan Die Zitrusblattminiermotte, P. citrella, tritt als wichtiger Schädling an Zitrusbäumen im Sudan und in anderen Ländern auf. Untersuchungen im Sudan zeigten, daß die Ei‐Entwicklung 2–6, die Entwicklung der 4 Larvenstadien 7–8 und jene der Puppen 8–9 Tage dauerten. Die Gesamtentwicklung von der Eiablage bis zum Schlüpfen der Motten beanspruchte im Winter 18 Tage. Der Schädling bevorzugte zur Eiablage die Blattunterseite. Gemessen an dem befallenen Areal, der Zahl lebender Larven und Puppen/Blatt und der Länge der Minen erwies sich die Grapefruit, Citrus paradisi, als die vom Schädling bevorzugteste Zitrusart. Es folgte die Limone, C. aurantiifolia, gefolgt von der Mandarine, C. nobilis. Die Gründe dieser Nahrungspflanzenwahl werden erörtert.