Search

The western flower thrips [Frankliniella occidentalis(Pergrande)] (Thysanoptera: Thripidae) is a major pest of greenhouse crops (Broadbent et al. 1987; van der Veire and Degheele 1992; Chambers et al. 1993). Chemical control of F. occidentalisis difficult because of its cryptic behaviour and widespread resistance to insecticides (Immaraju et al. 1992). The insidious flower bug, Orius insidiosus(Say), is widely promoted as an effective biological control agent for this pest (Chambers et al. 1993; van der Veire and Degheele 1992; Castane and Zalom 1994) and its use has increased steadily since their introduction in the late 1980s. When our project was initiated in 1989, O. insidiosuswas a little known and largely unavailable biological control agent. Now there are several domestic and international commercial sources of Oriusspp. and these predatory bugs have become a focus of research in Canada, the United States, and Europe. At first it was difficult and costly to maintain cultures of only 100 or 200 individuals but now we can rear 50000 — 100000 Oriusper week for less than $0.03 (Canadian) each.

We report two children who developed hypersensitivity reactions of varying severity following barium meal examination, the more severe of which was associated with documented severe food allergy. For children with this risk factor, contrast studies should be performed only where facilities and personnel are available for immediate resuscitation of all sizes of child. For children such as these, consideration should be given to the use of pure barium sulphate.

Host plant water status is thought to influence dispersal of the xylophagous leafhopper Homalodisca vitripennis Germar, especially where plants are grown under high evaporative demand. Preference by adult H. vitripennis for plants grown under different water deficit and nitrogen form fertilization regimens was studied under laboratory conditions. Leafhopper abundance and ovipositional preference were studied on potted ‘Washington navel’ orange and ‘Haas’ avocado in cage choice tests, and feeding rate was estimated using excreta produced by insects confined on plants. A similar study compared responses to citrus treated with 1:1 and 26:1 ratios of fertigated nitrate-N to ammonium-N. The insects were more abundant, oviposited, and fed significantly more on surplus-irrigated plants than on plants under moderate continuous deficit irrigation except avocado feeding, which was nearly significant. Plants exposed to drought became less preferred after 3 and 7 d in avocado and citrus, respectively. Citrus xylem fluid tension at this point was estimated at 0.93 MPa. A corresponding pattern of decline in feeding rate was observed on citrus, but on avocado, feeding rate was low overall and not statistically different between treatments. No statistical differences in abundance, oviposition, or feeding were detected on citrus fertigated with 26:1 or 1:1 ratios of nitrate-N to ammonium-N. Feeding occurred diurnally on both plant species. Discussion is provided on the potential deployment of regulated deficit irrigation to manage H. vitripennis movement as part of a multitactic effort to minimize the risk of disease outbreaks from Xylella fastidiosa Wells et al. in southern California agriculture.

Insect pollination of commercial annonaceous crops is variable among localities and poorly understood. To gain basic information for use in pollinator management programs, we studied the nitidulids that pollinate commercially grown sugar apples (Annona squamosa L.) and atemoyas (A. squamosa X A. cherimola P. Miller) in Florida. Only flowers visited by nitidulids set fruit. We found nine species of nitidulid flower visitors, seven of which pollinated. Carpophilus mutilatus Erichson was the most important pollinator in terms of efficacy and abundance, followed by C. fumatus Boheman and Haptoncus luteolus (Erichson). The Annona flowers, which are protogynous, are entered by the beetles usually during the female phase. Peak entry into atemoya flowers occurs in the morning (0700–0900 EST) and into sugar apple flowers both in morning (0700–1100) and evening (1700–2100). The beetles remain inside up to 22 h, until the flowers senesce and the stamens fall. In 1989, natural fruit set ranged from 0–29% of sampled flowers per day in atemoya groves and from 0–10% of flowers per day in sugar apples. Percentage of fruit set is correlated with numbers of nitidulids in the flowers.