The foraging behaviour of honey bees (Apis mellifera L.) on inflorescences of staghorn sumac [Rhus hirta Sudworth (ex-typhina L.)] was studied using a “choice table” placed in natural stands of this plant. The choice table consisted of a wooden grid with alternated male and female inflorescences of sumac. Honey bee activity was recorded also on inflorescences of naturally growing plants in which the secretion of nectar was measured and the anther dehiscence recorded. Honey bees were the only common pollinators observed on sumac in the study area. During the morning, both plant sexes secreted little nectar, and pollen was available after the dehiscence of the anthers which took place between 1000 and 1100 hours. Female inflorescences secreted great amounts of nectar during the afternoon, but in male inflorescences there was little secretion. Honey bees seemed to forage according to the circadian availability of resources. Most of their activity concentrated on male inflorescences in the morning and on female ones during the afternoon. Both the occurrence of bees with pollen loads in their corbiculae and the length of the visits to each sex also seemed to be in accordance to the kind of resource exploited at particular times of the day. Most of the bees with pollen loads were observed during the morning and the longest visits to any inflorescences were registered on female ones during the afternoon (by bees foraging for nectar). Despite our results suggesting that the pollination success of staghorn sumac would be impaired by the foraging pattern of honey bees, an explanation is proposed for its reproductive success.

In a 3-year field study, potted plants of ‘Katepwa’ wheat, Triticum aestivum L., were exposed to ovipositing wheat midge. Sitodiplosis mosellana (Géhin), to determine when spikes are most susceptible to damage. After exposure, plants were maintained under controlled conditions for 4 weeks and examined for wheal midge larvae and damaged kernels, ‘Katepwa’ wheat became susceptible to wheat midge damage shortly after spikes emerged from the boot leaf. Location of larvae and damaged kernels within spikes was influenced by the duration spikelets were exposed to oviposition and pattern of anthesis within spikes. In 1992, frequencies of larvae and damaged kernels were 60–90 times higher in spikes exposed to oviposition during advanced heading (stages 57–59, Zadoks’ code) than in those exposed during flowering (stages 61–69). Kernel damage in spikes exposed to oviposition during stages 57–59, 61–65, and 65–70 was 48.5, 3.2, and 0.2%, respectively, in 1993 and 21.2, 1.0, and 0.6%, respectively, in 1994. Data indicated that susceptibility to midge damage declined 15- to 25-fold between heading and early anthesis and 35- to 240-fold between heading and advanced anthesis. Potential factors contributing to these declines and concomitant reductions in larval frequencies are discussed.

Commercial fields of ‘Katepwa’ wheat should be monitored for ovipositing wheat midge throughout heading (stages 51–59) when spikes are most vulnerable to damage. Larval survival and kernel damage were so low after stage 61 that monitoring during anthesis should be unnecessary. Intensive inspection of fields throughout heading would ensure that chemical treatments are applied when they are necessary and most effective.

The seasonal phenology of the walnut husk fly (WHF), Rhagoletis completa Cresson, was studied in the Willamette Valley of Oregon during a 4-year period (1990–1993). Adult emergence observed in ground emergence cages varied greatly among years. Initial emergence ranged from 29 June to 17 July, and last emergence occurred as early as 17 August or as late as 11 September. The period of adult emergence was constant from year to year (mean 55, range 50–60 days) with the peak between the 3rd week of July and the 1st week of August. The period between first observed appearance of females in ground-level emergence cages and the first oviposition was consistent among the study years, ranging from 20 to 23 days. Peak oviposition occurred in the 2nd and 3rd weeks of August. Mean egg hatch and larval survival were 98 and 80%, respectively. Infestations reached over 95% in unsprayed trees by early to mid September. Mature larvae first exited from husks beginning the 4th week of August and continued through mid October. Larvae penetrated the soil and pupated at a depth of 2.5–7.6 cm with most within the top 2.5 cm of soil.

From 1989 to 1993, trunk implants of acephate were tested for the control of seed and cone insect damage to conifer species in France and northeastern China. The treatments were promising for the control of the major pests that feed on cone and seed tissues, including cone flies, coneworms, and seedworms, in European and Siberian larch, Norway spruce, Scots and mountain pine. In contrast, acephate implants did not prevent seed chalcid damage nor that of gall midges in Douglas-fir, European larch, and Siberian larch. Treatment generally increased seed yield, but a significant increase in the number of filled seeds was seen only when chalcids and midges were absent. The 2-year effect of implants seemed limited. Acephate implantation did not seem to affect seed germination.

The use of potato as a trap crop for the Colorado potato beetle, Leptinotarsa decemlineata (Say), in processing tomatoes was evaluated. The proportion of beetles counted on potato trap rows vs. the tomato crop on a per plant basis was 0.99, 1 week after transplanting, and never fell below 0.93 on any sampling date. In tomato plots that received no insecticides, potato trap rows placed as much as 16 tomato beds apart were effective in reducing beetle numbers on the tomatoes and producing crop yields 61–87% higher than plots without trap rows. Four of six pairs of plots had significantly fewer adult beetles and significantly higher tomato yields when a potato trap crop was present.

Although the structure of the ovipositor of parasitic Hymenoptera is largely uniform, interspecific variation in its morphology can be observed. Such variability may be related to the diversity of hosts attacked. To verify such an hypothesis, we compared, using correspondence analysis, the morphological characteristics of the ovipositors of 20 species in three categories: (i) species belonging to the same taxonomic unit and attacking the same type of host, (ii) species belonging to the same taxonomic unit but attacking different types of host, and (iii) species belonging to different taxonomic units but attacking the same type of host. Results show that variability in some morphological traits of the ovipositor can be related to host characteristics. Adaptive convergence in morphological variations observed between species is discussed.

The native elm bark beetle, Hylurgopinus rufipes (Eichhoff), is the major vector of Dutch elm disease, Ophiostoma ulmi (Buisman) Nannf., in Manitoba. The herbicide Glowon™, monosodium methane arsenate (MSMA), was applied to a chainsaw cut in American elm, Ulmus americana L., tree stems to determine if the treated elms would become effective trap trees for H. rufipes. Three treatments were compared: treated with herbicide and girdled, girdled, and control. All herbicide-treated elms died within 18 days after application. Significantly higher numbers (P < 0.01) of native elm bark beetles were attracted to the herbicided elms, compared with the other treatments. Beetles bred only in the elms treated with herbicide. Of the total brood galleries constructed, 72% had no egg hatch while the remaining 28% had larval tunnels. Progeny adults emerged from less than 1% of the larval tunnels. MSMA application could supplement the Dutch elm disease management program in Manitoba.

Eight genera and 25 species are recognized among the Nearctic, Mexican, and West Indian Oodini. Four new species are described: Oodinus pseudopiceus (type locality: Hillsborough River St. Pk., Hillsborough Co., Florida); Oodinus similis (type locality: San Quintín, Chiapas, Mexico); Oodinus darlingtoni (type locality: Cauto El Cristo, Oriente, Cuba); and Oodinus edentulus (type locality: 31.8 mi E Francisco Escárcega, Campeche, Mexico). Oodes fluvialis LeConte, 1863, previously recognized as a subspecies of O. americanus Dejean, 1826, is given specific status. The following new synonymies are established: Eulachnocrepis Habu, 1956 with Lachnocrepis LeConte, 1853; Stenocrepis texana (LeConte, 1863), S. chalcas Bates, 1882, and S. chalcochrous Chaudoir, 1883 with S. insulana (Jacquelin du Val, 1857); Stenocrepis quatuordecimstriata (Chaudoir, 1843), S. picipes (LeConte, 1844), S. stenocephala (LaFerté-Sénectère, 1851), and S. sulcata Chevrolat, 1863 with S. mexicana (Chevrolat, 1835). Lectotypes are designated for Oodinus alutaceus (Bates, 1882), Oodes amaroides Dejean, 1831, O. fluvialis LeConte, 1863, O. americanus Dejean, 1826, Stenocrepis texana (LeConte, 1863), S. chalcas Bates, 1882, S. lecontei (Chaudoir, 1857), S. quatuordecimstriata (Chaudoir, 1843), S. picipes (LeConte, 1844), S. cuprea (Chaudoir, 1843), S. tibialis (Chevrolat, 1834), S. femoralis (Chaudoir, 1835), S. elegans (LeConte, 1851), and S. gratiosa (Bates, 1882). The genus-group name Nanodes Habu, 1956, a homonym of Nanodes Schönherr, 1825, is replaced by Nanodiodes, new replacement name. For each genus treated, the following are provided: citation of original description and selected references, notes about synonymy (if required), description, geographical distribution and diversity, and monophyly and phylogenetic relationships. For each species included, the following are given: citation of original description and synonymies, type material, etymology (for new species only), notes about synonymy (if required), diagnosis, description, geographical distribution, bionomics, and phylogenetic relationships (if the genus includes more than two species). Keys to genera and, for each genus, to species are included. The species distributions are mapped, and the important structural features are illustrated.