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Efforts to prevent temperature increases in streams and rivers have led to regulation of the maximum permissible temperature for wastewater discharges. Hyporheic discharge treatment, where warm wastewater is allowed to infiltrate into the soil and percolate toward the stream, has been proposed as an alternative management practice, potentially providing increased streamflow at decreased temperature. To assess the feasibility of such a system, a pilot study was performed in which groundwater level, temperature, and chemistry were monitored to characterize percolation from a 0.15-ha infiltration wetland. The temperature patterns suggested that water seepage rates exceeded 1.6 md-1 near the wetland, while the chemistry data indicated that infiltrated water had laterally percolated more than 100 m during the study period. The water level and temperature measurements were also used to calibrate a software model. Observations and simulations showed that the local water table became directly connected to the wetland. As a result, much of the water infiltrated through the wetland perimeter rather than through the wetland center, which implies that specific infiltration rates will decrease with increasing wetland size. This theory was tested using two approaches: (1) numerical simulation of a large-scale (5.5 ha) infiltration wetland; and (2) a water budget performed on an adjacent low-lying, inundated section of the floodplain, which due to its topography was considered to be an accurate approximation of the performance of a large-scale system. The water budget approach indicated a mean seepage velocity of 0.08 md-1, which was essentially equal to the predicted seepage velocity for a large-scale infiltration wetland of 0.077 md-1. [ABSTRACT FROM AUTHOR]

The application of insecticides is an essential component for eradication or management of fruit fly pests. Impact on nontarget organisms and public rejection of areawide pesticide applications have been major concerns in managing these programs. Bait stations have been proposed as alternative treatments in areas where broadcast insecticides are not acceptable. In this study, we defined bait stations as discrete containers of attractants and toxins, which are targeted at specific pests. Tests were carried out using the Mexican fruit fly, Anastrepha ludens (Loew), as the experimental insect. Our first bait station design was a sheet of sponge material fastened to a plastic peaked cover. Liquid bait consisting of protein hydrolyzate, sugar, adjuvants, a photoactive dye toxicant, and other additives was applied to the sponge. This station, when tested in an orchard, reduced sterile released adult populations by 70–90% in 4 d compared with check plots. Other tests in field cages showed that the bait station was ≈22% less effective in killing adults compared with spot sprays on trees. We formulated a gelled bait by using a more refined hydrolyzed protein, supplemental attractants, feeding stimulants, and additives to protect the bait from drying. A series of experiments were carried out in field cages by using a cylindrical bait station that provided improved protection of the bait. These tests showed that there is a gradual decline in bait effectiveness with age. [ABSTRACT FROM AUTHOR]

A maximum pest limit approach is used to determine the probability of pest introduction into the United States when commodities are hoststo the Mexican fruit fly, Anastrepha ludens (Loew). Ecological parameters including proportion of fruit infested and the number of pests per infested fruit were collected under various pest management scenarios for mangoes and citrus in regions of Mexico that are infested with Mexican fruit fly. Various calculations were performed using techniques developed by statisticians in New Zealand and the United Statesto determine the probability of a single reproductive pair of Mexican fruit flies surviving in a shipment of fruit, or the required post-harvest insecticidal treatment of fruit that would be required to assure that a reproductive pair did not survive. Results indicated that Mexican fruit fly host infestation levels under conditions with no pest management will frequently allow survival levels exceeding this maximum pest level following a postharvest treatment that has been shown to be at least 99.9968% effective. Standard pest management practices such as insecticide application, sterile insect release, or the selective harvest of fruit reduced the predicted survival rate in treated fruit to levels below 2 flies per shipment. This approach suggeststhat the requirement for a postharvest quarantine treatment with demonstrated efficacy corresponding to at least 99.9968% (probit 9) mortality is effective in maintaining a predicted pest survival of cl reproductive pair of flies per shipment only when combined with current pest management practices. [ABSTRACT FROM AUTHOR]

Two artificial larval diets were developed for the West Indian fruitfly Anastrepha oblique (Macquart). One was a papaya diet containing torula yeast, corn flour, fresh papaya pulp, and sugar; this diet provided essential nutrients needed for larval development and produced sufficient numbers of flies for further testing. The other, a casein diet, included torula yeast, corn flour, casein, sugar, minerals, andvitamins. The use of casein was a suitable replacement for papaya; pupal production increased 1.5 times. We reared A. oblique for 24 generations in papaya diet and 39 generations in the casein diet without loss of fecundity. Two other diets containing defatted soy flour or dehydrated pea powder in place of casein, produced similar numbers of pupae as the papaya diet. Raw or stabilized wheat germ inhibited larval development. When crude lipids were removed from wheat germ, recoveries of larvae, pupae, and adults were similar as in the casein diet. Addition of low amounts of Beck's salt mixture to casein diet increased adult recovery compared with the control, but salt concentrations >0.1% significantly decreased recoveries of larvae, pupae, and adults. Addition of vitamins to casein diet were not proven essential in the generation tested. [ABSTRACT FROM AUTHOR]