When last instar laboratory-reared Rhagoletis indifferens were allowed to pupate within non-sterile orchard soil containing incorporated Metarhizium brunneum isolate F52 conidia, a dose-related ...proportion died from developmental abnormalities and mycosis. When larvae entered soil superficially treated with M. brunneum, over 80% of the pupae died of developmental abnormalities.
The western cherry fruit fly, Rhagoletis indifferens Curran, infests introduced, domesticated sweet Prunus avium (L.) L. , and tart cherries (Prunus cerasus L.) as well as native bitter cherry, ...Prunus emarginata (Douglas) Eaton. Bitter cherries are smaller than sweet and tart cherries and this could affect various life history traits of flies. The objectives of the current study were to determine 1) if body size and egg loads of flies infesting sweet, tart, and bitter cherries differ from one another; and 2) if any observed body size differences are genetically based or caused by the host fruit environment. Pupae and adults of both sexes reared from larval-infested sweet and tart cherries collected in Washington and Montana were larger than those reared from bitter cherries. In addition, flies of both sexes caught on traps in sweet and tart cherry trees were larger than those caught in bitter cherry trees and females trapped from sweet and tart cherry trees had 54.0–98.8% more eggs. The progeny of flies from naturally-infested sweet and bitter cherries reared for one generation in the laboratory on sweet cherry did not differ in size. The same also was true for progeny of sweet and bitter cherry flies reared in the field on bitter cherry. The results suggest that the larger body sizes of flies from sweet and tart cherries than bitter cherries in the field are caused by host fruit and not genetic factors.
Western cherry fruit fly, Rhagoletis indifferens Curran 1932 (Diptera: Tephritidae), was reared from naturally-infested Chinese crabapple, Malus spectabilis (Aiton) Borkhausen (Rosaceae), in ...Washington State, U.S.A. Pupae from Chinese crabapple were smaller than those from sweet cherry, Prunus avium (Linnaeus) Linnaeus (Rosaceae), but fecundity and longevity of flies from the two hosts did not differ. Laboratory experiments were conducted to compare larval development in crabapples and cherries. ‘Snowdrift’ crabapples (Malus × ‘Snowdrift’) did not produce pupae. Percentages of ‘Indian Magic’(Malus ‘Indian Magic’) + ‘Radiant’ crabapple (Malus ‘Radiant’) vs. sweet cherry replicates that produced pupae did not differ in two no-choice experiments (36.7 vs. 41.7% and 13.3 vs. 33.5%, respectively). In a choice experiment, the percentage of crabapple replicates that produced pupae (6.7%) was lower than that of cherry replicates (42.2%). Egg to pupal development times in crabapples (18.0–21.2 d) were longer than in cherries (15.4–16.7 d) and pupae from the crabapples were smaller. Results suggest crabapples are not optimal developmental hosts for R. indifferens but that Chinese and ‘Indian Magic’ + ‘Radiant’ crabapples can occasionally allow late-season flies to bridge the gap between one generation and the next when no cherries are available.
Although flight is believed to be the primary mechanism for dispersal in the Western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephritidae), an orchard pest of both sweet (Prunus ...avium L.) and sour (Prunus cerasus L.) (Rosaceae) cherry crops, the movement of these flies between host patches is difficult to quantify in the field. A tethered flight mill system was used in the laboratory to examine the flight behaviour of sexually mature flies exposed to different levels of conspecific contact and resource availability. A complete 2 x 2 x 3 factorial design compared the relative influence of the factors 'context' (crowded, isolated), 'sex' (female, male), and 'resources' (low = food only; medium = food + leaf; high = food + leaf + cherries) on flight performance measures including distance flown, net trial time, and stopping patterns. Rather than using a minimum time or distance to determine trial length, flight observations were continued for each fly until a behavioural protocol based on stopping time was met. In this protocol each successful trial was composed of three consecutive flight intervals and included a minimum of three stops lasting a combined total of 5 min. Of the 160 flies tested, 86.9% flew <500 m on the flight mill. Individuals from both sexes were capable of maximum flights in the same order of magnitude, ca. 3 km on the flight mill. Distance flown was significantly influenced by 'context' such that crowded individuals flew >1.5-fold farther than isolated individuals. Sex influenced the frequency and duration of stops made, with females stopping more often and longer than males. Although females and males in high resource treatments had the shortest net trial times, the factor 'resources' did not produce any highly significant main effects, but did generate significant interaction terms with the factors 'context' and 'sex', suggesting that past experience with 'resources' modifies individual flight behaviour. We have shown for the first time using a tethered flight mill system that R. indifferens flight behaviour is context dependent and sensitive to adult crowding. The implications of this study for improved field experiments on dispersal are discussed.
The effects of spinosad bait and various insecticides, the presence of sugar in insecticides, and diet on feeding responses and mortality in western cherry fruit fly, Rhagoletis indifferens Curran ...(Dipt., Tephritidae), were determined. Numbers of feeding events on insecticides with sugar were greater than on insecticides alone, but there was only a small effect of diet on feeding responses to insecticides with sugar. Feeding durations on imidacloprid, thiamethoxam and acetamiprid with sugar were shorter than on sugar water and spinosad bait, as the neonicotinoids paralysed flies quickly. Flies that fed on sugar only (nitrogen‐starved) suffered higher mortalities when exposed to spinosad, thiamethoxam and azinphos‐methyl than to imidacloprid, acetamiprid and indoxacarb, and mortality in between these two groups of treatments when exposed to spinosad bait. Mortalities were greater when sugar was added to insecticides, and were higher in nitrogen‐starved than fully‐fed (yeast extract + sugar fed) flies. Flies that fed once on thiamethoxam were killed more quickly than those that fed once on spinosad bait and spinosad. Results suggest that thiamethoxam is comparable to spinosad in its effects on mortality, and that using it with sugar in bait may also have similar results as using spinosad bait or spinosad. One benefit of using thiamethoxam with sugar may be that it kills flies more quickly, before they can oviposit, than spinosad bait, although whether a fly will feed on it may depend on how much sugar or nitrogenous food it has eaten.
Organic production of pome and stone fruits in the United States has greatly increased during the past few years. To compete and enter lucrative export markets, these fruit must meet stringent ...quarantine requirements. For some countries, these requirements dictate that the fruit crops must be treated with a synthetic chemical fumigant, which is not compliant with organic standards. Therefore, nonchemical quarantine treatments for organically produced pome and stone fruits have been developed using the Controlled Atmosphere/Temperature Treatment System (or CATTS) technology. This technology applies a short-term heat treatment under a low-O2/high-CO2 environment, and is effective in controlling the most prominent quarantine insect pests while maintaining commodity quality. The technology has progressed beyond laboratory-scale research units to 1- to 2-ton commercial units. The development of these treatments and their effect on both insect mortality and commodity quality are discussed.
The effect of altitudinal variation on the seasonal flight activity of Rhagoletis cerasi (Linnaeus) flies was evaluated along an altitudinal gradient from 150 to 1170 m in Mount Uludag, northwestern ...Turkey. The predicted dates of fly emergence, flight duration and dates of 5%, 50% and 95% cumulative fly catches at various altitudes were estimated from a degree-day model. Degree-day predictions were compared with those obtained from observations made with yellow sticky traps. The observed and predicted dates of appearance of adults were delayed by 1.4 and 2.0 days for every 100 m increase in altitude, respectively. The delay in phenology events was less at high altitudes than postulated by Hopkins’ bioclimatic law, whether observed or predicted. The average absolute difference in predicted and observed dates of cumulative percentage catch of adults was 4.9 and 3.0 days in 1997 and 1998, respectively, but these differences were not significant. Prolonged flight activity was predicted and observed at higher altitudes, but the flight period lasted significantly longer than predicted. The observed flight period varied from 29 to 43 days in 1997 and from 36 to 52 days in 1998 between the lowest and highest altitude on the transect. Altitudinal variation between geographically close locations should be taken into account to properly time monitoring activities and hence to manage R. cerasi populations more effectively.
Western cherry fruit fly, Rhagoletis indifferens Curran (Diptera: Tephritidae), is the major quarantine pest of sweet cherry, Prunus avium (L.) L. (Rosaceae), in the Pacific northwest of the USA and ...in British Columbia in Canada. Although spinosad bait (GF-120 NF Naturalyte® Fruit Fly Bait) is used for the control of R. indifferens in this region, the effects of alternate food sources on fly responses to this bait have not been studied. In this study, experiments were conducted to determine mortalities of flies exposed to hydrolyzed protein baits in the presence of sugar only and sugar + yeast extract food. All baits contained Entrust® (termed 'spinosad alone'). When flies were exposed to GF-120 with or without added ammonia compounds (uric acid, ammonium acetate, and ammonium carbonate) for 48 h, mortalities were higher in the presence of sugar only than in the presence of sugar + yeast extract, but when flies were exposed to spinosad alone, mortalities were similar in presence of either of the two foods. In another experiment comparing GF-120, Nu-Lure, Mazoferm, Baker's yeast extract, and spinosad alone, mortalities in the GF-120, Mazoferm, and Baker's yeast extract treatments were higher in the presence of sugar only than in the presence of sugar + yeast extract, but in the Nu-Lure and spinosad alone treatments, mortalities were similar in the presence of either of the two foods. Overall results suggest that the indirect effects of yeast extract food on mortality are dependent on bait type and that mortalities caused by spinosad alone and baits are similar. Nu-Lure and spinosad alone may have an advantage over other treatments for fly control, because their effects do not appear to be affected by the presence of nitrogenous food.
GF-120 is a baited formulation of the insecticide spinosad containing 1% ammonium acetate, developed for control of economically important fruit flies. The response of feral cherry fruit flies, ...Rhagoletis cingulata Loew, to GF-120 augmented with 0, 5, or 10% ammonium acetate was evaluated under orchard conditions. Significantly more flies were observed within 30 cm of bait droplets with 10% ammonium acetate added compared with standard bait or to a water control. These fly visits to GF-120 enhanced with 10 or 5% ammonium acetate lasted an average of 263.2 ± 85.2 and 337.6 ± 72.6 s, respectively, compared with 50.3 ± 36.4 s for standard GF-120. Droplets containing additional ammonium acetate also were contacted by more flies, and more flies fed upon these droplets than on GF-120 or the water control. Furthermore, the duration of feeding on GF-120 bait enhanced with either level of additional ammonium acetate was significantly greater compared with standard GF-120 or water. Feeding events lasted between 61.5 ± 30.7 and 73.4 ± 21.0 s on enhanced GF-120 compared with 6.8 ± 5.7 s on standard GF-120. Collectively, these results indicate that the interaction of feral R. cingulata with GF-120 droplets and the toxicant spinosad can be increased by addition of ammonium acetate.
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