The Canadian Entomologist 126: 11 11 -11 18 (1994) The geographic range of the Douglas-fir twig beetle, Pityophthorus orarius Bright, was extended beyond the original provenance of southern British Columbia to northern California. A survey of 457 Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] trees in 1985 revealed that those with heavy cone crops were more likely to be infested by twig beetles than were those with a light crop. Furthermore, attack rates differed among clones. A second survey done in 1987 confirmed the importance of clone and cone crop in attack rate. In this survey, stressed trees were attacked at a higher rate than unstressed trees. Beetle distributions appeared clumped in both surveys, possibly because of semiochemicals or oviposition behavior. Rappaport, N.G., et D.L. Wood. 1994. Pityophthorus orarius Bright (Coleoptera: Scolytidae) dans un verger ? i graines du sapin de Douglas au nord de la Californie: Effet de clone, classe de vigeur, et nombre de c6nes sur le taux d'attaque. The Canadian Entomologist 126: 1 11 1-1 118. ResumeLe scolyte des brindilles du sapin de Douglas, Pityophthorus orarius Bright, dont la repartition gkographique Ctait limitCe au sud de la Colombie Britannique, a Ct C rCcolt6 dans le nord de la Californie. Un relev6 effectuC en 1985 sur 457 sapins de Douglas, Pseudotsuga rnenziesii (Mirb.) Franco, a rCvClC que le taux d'attaque des c6nes d'un arbre Ctait liC B son niveau de fructification; les plus fructifkres Ctant attaquCs par plus de scolytes que ceux produisant peu de c6nes. De plus, nous avons observC une corrClation positive entre les taux d'attaques et les clones de sapins. Un second relev6 exCcutC en 1987 a corroborC l'influence de la souche clonale et du niveau de fructification sur le taux d'attaque, en plus d'indique que les arbres considCr6s stressCs Ctaient plus sensibles B l'attaque du scolyte que ceux sans stress. La distribution concentrte des scolytes observCe lors de ces deux relevCs est peut Ctre like au comportement de ponte ou aux substances sCmio-chimiques.

The calling behaviour of 0‐day‐old and 2‐day‐old virgin female eastern spruce budworm moths, Choristoneura fumiferana (Clem.) was observed during exposure to different concentrations of the synthetic female sex pheromone. Regardless of whether the females were exposed to pheromone or not, there were two daily peak periods of calling activity, one in the afternoon and the other after dusk. Those moths exposed to pheromone commenced calling at least 2 h earlier during their first peak of calling activity. Also, a greater number of moths engaged in calling when exposed to pheromone than those under control conditions. RÉSUMÉ Modification du comportement d'appel des femelles de Choristoneura fumiferana exposées à la phëromone sexuelle synthétique de leur propre espèce. Des expériences ont été menées au laboratoire pour examiner si la phéromone sexuelle synthétique de C. fumiferana pouvait altérer le comportement d'appel de femelles vierges de la même espèce. Un appareil a été conçu pour libérer alternativement ‐ à des intervalles déterminés ‐ un courant d'air portant de la phéromone sexuelle ou un courant d'air pur, dans plusieurs flacons contenant des femelles vierges. Le comportement sexuel de mouches de 0 et 2 jours a ainsi été observé. Indépendamment de l'exposition des femelles à la phéromone, il y avait deux pics quotidiens d'activité d'appel, l'un dans l'après‐midi et l'autre après le crépuscule. Des papillons exposés au 1 × 10−6 mg ou 1 × 10−3 mg de phéromone avaient un premier pic d'appel au moins antérieur de 2 heures par rapport aux témoins. Ainsi il y avait un plus grand nombre de papillons engagés dans une activité d'appel en présence de la phéromone que chez les témoins.

Can. Ent. 124: 895-906 (1992) A laboratory method to screen crucifer seedlings for antixenosis resistance to flea beetles, Phyllotreta cruciferae (Goeze), is described. The method utilizes a plexiglass arena with a foam base to hold 30-by 50-rnm vials containing individual seedlings of 10 entries (10 seedlings per entry) in a 10 x 10 layout. In each arena, nine test entries and a standard entry are compared in a Latin square design. Flea beetles are allowed to feed on seedlings for about 30 h, and then the damage to individual seedlings is estimated using a visual rating scale. A rating of one arena can be completed in about 15 min. Seedlings at the arena edge often suffer more damage than those in the centre of the arena, but the effect of this variability in damage is minimized by the Latin square design. Use of border (guard) rows and columns does not eliminate the edge effects. The use of arenas without borders, and a single damage rating where the damage to the standard entry is about 50% of the cotyledon area, are considered ideal for initial screening to identify sources of flea beetle resistance. The method detects entries that differ by as little as 18% damage using a single arena with 10 replicate seedlings per entry. No significant antixenosis was found among 19 cultivars of Brassica napus L. and B. campestris L., but one accession of B. carinata L. and two accessions of Sinapis alba (L.) exhibited antixenosis. Palaniswamy, P., R.J. Lamb et P.B.E. McVetty. 1992. Identification des plants rksistants a 1'Altise des cmciferes, Phyllotreta crucifers (Goeze) (Coleoptera: Chrysomelidae), parmi des plants de colza et d'autres cruciferes apparent6es. Can. Ent. 124: 895-906.

Sinigrin (allyl glucosinolate), the major glucosinolate in the cotyledons ofBrassica juncea cv. Cutlass, occurred in the highest concentration and amount at seedling emergence and declined during growth. Glucobrassicin (3-indolylmethyl glucosinolate), the major glucosinolate in the cotyledons ofB. napus cv. Westar, occurred in the lowest concentration and amount at seedling emergence. The amount of glucobrassicin per cotyledon pair increased about fourfold during 14 days of growth, but its concentration remained relatively unchanged because of "dilution" by increasing cotyledon biomass. These different glucosinolate profiles indicate a different metabolic control and different biological function for sinigrin and glucobrassicin. The flea beetle,Phyllotreta cruciferae Goeze, does not discriminate between cotyledons having sinigrin or glucobrassicin since the two crucifers were fed upon equally in choice tests. Restricting the concentration of sulfur in the nutrient medium accelerated the decline of sinigrin inB. juncea cv. Cutlass but did not alter the feeding rate ofP. cruciferae compared to controls. Sulfur restriction reduced glucobrassicin inB. napus cv. Westar to undetectable levels and somewhat reduced the feeding rate of P.Cruciferae. Nevertheless,P. cruciferae still fed actively on cotyledons ofB. napus cv. Westar depleted of glucosinolates and severely damaged many of them. Since glucosinolate type and concentration had little effect on feeding response, reduction or elimination of foliar glucosinolates alone would not seem a useful strategy for protecting seedlings of these two crucifers from flea beetle damage.

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In addition to three known sex lure components [(Z)-11-hexadecenyl acetate, (Z)-11-hexadecenal, and (Z)-11-hexadecenol], (Z)-9-tetradecenyl acetate was field-proven as a trace coattractant for malePlutella xylostella, with an optimal content below 0.01% in blends. This potent four-component lure for diamondback males also attractedCrymodes devastator males, and in this respect is not different in its attractancy from virgin diamondback females. Replacement of (Z)-9-tetradecenyl acetate in the four component lure with (Z)-9-tetradecen-1-ol, at the level of 10% of the total lure mixture, did not alter its attractancy for diamondback males, but it did inhibit attraction ofCrymodes devastator. The status of biologically active components as possible sex pheromones or para-pheromones is discussed.

Can. Ent. 122: 817-824 (1990) The flea beetle, Phyllotreta striolata (F.), was attracted to the cruciferous plants Brassica oleracea L. and Raphanus sativus L., but not to B. campestris L. and B. napus L. which are important natural host plants, nor to Pisum sativum (L.), a legume. The presence or absence of attraction was demonstrated by exposing small groups of caged plants to natural populations and trapping beetles near the plants. In choice and nochoice laboratory feeding experiments, P. striolata fed on eight Cruciferae in the genera Brassica, Raphanus, and Sinapis but not on P. sativum. Phyllotreta striolata fed less on S. arvensis L. and S. alba L. than on plants in the other genera. Within Brassica, B. oleracea, B. napus, and B. campestris were preferred over B. juncea (L.) Czern and B. nigra (L.) Koch. Discrimination at the attraction phase of host selection did not account for discrimination shown in laboratory feeding experiments nor in the natural attack of flea beetles on cruciferous crops. Lamb, R.J., et P. Palaniswamy. 1990. Discemement de I'h6te par l'altise des navets, Phyllotreta striolata (F.) (Coleoptera: Chrysomelidae). Can. Ent. 122: 817-824. Resume L'altise des navets, Phyllotreta striolata (F.), Ctait attirCe par les plantes cruciferes Brassica oleracea L. et Raphanus sativus L., mais pas par B. campestris L. et par B. napus L., qui sont des plantes-h6tes naturelles importantes, ni par Pisum sativum (L.), une 16gumineuse. La prCsence ou l'absence d'attraction a Cte d6montrCe en exposant des petits groupes de plantes encagCes aux populations naturelles et en attrapant les altises proche aux plantes. Aux expCriences d'alimentation au laboratoire prksentant du choix ou non, P. striolata s'est nourri de huit cruciferes du genre Brassica, Raphanus, et Sinapis, mais pas de P. sativum. Phyllotreta striolata s'est nourri moins aux plantes de S. arvensis L. et de S. alba L. qu'aux plantes des autres genres. Parmi les Brassica, les plantes de B. oleracea, B. napus et B. campestris Ctaient prCfCr6es a celles de B. juncea (L.) Czern et de B. nigra (L.)Koch. Le discernement B la pCriode d'attraction pour la sClection d'h6tes n'a pas Ct C justifie par le discernement dCmontrC aux experiences d'alimentation au laboratoire ni a l'attaque de l'altise aux plantations cruciferes.

No abstract