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Seasonal adaptations to daylength often limit the effective range of insects used in biological control of weeds. The leaf beetle Diorhabda carinulata (Desbrochers) was introduced into North America from Fukang, China (latitude 44° N) to control saltcedars (Tamarix spp.), but failed to establish south of 38° N latitude because of a mismatched critical daylength response for diapause induction. The daylength response caused beetles to enter diapause too early in the season to survive the duration of winter at southern latitudes. Using climate chambers, we characterized the critical daylength response for diapause induction (CDL) in three ecotypes of Diorhabda beetles originating from 36, 38, and 43° N latitudes in Eurasia. In a field experiment, the timing of reproductive diapause and voltinism were compared among ecotypes by rearing the insects on plants in the field. CDL declined with latitude of origin among Diorhabda ecotypes. Moreover, CDL in southern (<39° N latitude) ecotypes was shortened by more than an hour when the insects were reared under a fluctuating 35-15°C thermoperiod than at a constant 25°C. In the northern (>42° N latitude) ecotypes, however, CDL was relatively insensitive to temperature. The southern ecotypes produced up to four generations when reared on plants in the field at sites south of 38° N, whereas northern ecotypes produced only one or two generations. The study reveals latitudinal variation in how Diorhabda ecotypes respond to daylength for diapause induction and how these responses affect insect voltinism across the introduced range.

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A prototype of a device that relays navigational information to a person who is visually impaired using a portable tactile glove and a wearable computer and camera system was demonstrated and tested. The results of preliminary tests using the glove as a navigational device show that the paths traversed by subjects negotiating an obstacle course using the glove were not qualitatively different from the paths produced with existing wayfinding devices and that hitting probabilities, the measure of the likelihood of hitting an obstacle, are minimized from goal-directed random walks.

In laboratory studies and experimental packingline trials that closely simulated fungicide treatments under commercial conditions, the “reduced-risk” fungicides fenhexamid and fludioxonil were highly effective in managing postharvest brown rot and gray mold decays of peach, nectarine, and plum caused by Monilinia fructicola and Botrytis cinerea, respectively. Tebuconazole was more effective against brown rot than against gray mold. Additionally, fludioxonil and tebuconazole significantly reduced the incidence of Rhizopus rot caused by Rhizopus stolonifer. In laboratory studies, the QoI fungicide azoxystrobin was not consistent in its decay control activity. The high efficacy of fenhexamid and fludioxonil against brown rot and gray mold was substantiated by low effective concentrations necessary (≤0.063 mg/liter)for 50% inhibition of mycelial growth in vitro. In general, fungicides applied 14 to 16 h after wound inoculation were significantly more effective than those applied before inoculation. These results indicate that the fungicides act mainly as protectants that do not penetrate deeply enough into the fruit to prevent decay from wounds that extend below the fruit epidermis. Laboratory treatments of plum fruit generally were less effective than those of peach or nectarine fruit. Comparative studies using either low-volume spray or high-volume, in-line drench applications over a roller bed demonstrated that drench applications were significantly more effective in reducing postharvest decaysof inoculated plum fruit. Decay incidence using fenhexamid or fludioxonil was ≤1.1%, whereas incidence after the spray applications was between 25.2 and 40.4% for brown rot, between 12.0 and 24.3% for gray mold, or 62.6% for Rhizopus rot (fludioxonil only). This research identified effective replacements for iprodione, a fungicide voluntarily canceled by the manufacturer in 1996.