Effect of Abundance of the Navel Orangeworm on Sampling Range and Interference Between Pheromone Traps

2014

Environ Entomol

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The navel orangeworm, Amyelois transitella (Walker) (Lepidoptera: Pyralidae), is a key pest of almond, pistachio, and walnut tree crops in California. Understanding dispersal of adults between orchards is important to improving management options. Laboratory flight behavior of unmated navel orangeworm of ages 1, 2, 3, 5, and 7 d posteclosion was examined using flight mills. As a group, females flew farther and longer than males, but the differences were not statistically significant. Flight speed did not differ between sexes. Flight duration and distance did not differ with age, except that 7-d-old adults performed worse for these parameters than did 1- and 2-d-old adults. Females began their flights ≍1.5 h after the onset of dusk, and ≍1.5 h earlier in the night than males. Flight capacity and propensity were substantial for both sexes and all age classes tested. At least 20% of adults (except 7-d-old males) made a continuous flight ≥5.5 h, and median total distances flown during the 10.5-h night ranged from 7 to 15 km depending on age class. Thus navel orangeworm flight mill performance was greater than that of most pests tested from the families Pyralidae and Tortricidae. Surface area and length of forewings and hindwings were greater in females than males, but had little effect on flight performance. The results are generally consistent with field observations of navel orangeworm dispersal, but it will be important to characterize the effects of mating on flight, and flight on fecundity.

Section: Discussionmentioning

confidence: 76%

mentioning

confidence: 99%

Patterns of Flight Behavior and Capacity of Unmated Navel Orangeworm (Lepidoptera: Pyralidae) Adults Related to Age, Gender, and Wing Size

Sappington

2014

Environ Entomol

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“…The robust dispersal capacity of adults may help explain the challenges encountered with this species when developing treatment thresholds based on pheromone trap data (Burks et al., ; Burks & Higbee, ). The number of males captured in a pheromone trap is dependent on the distance over which the plume is attractive, and the distance travelled within the sampling period before encountering the plume (i.e., trapping radius) (Wall & Perry, ; Miller et al., ; Adams et al., ).…”

Section: Discussionmentioning

confidence: 99%

Interrelation of mating, flight, and fecundity in navel orangeworm females

Rovnyak

Entomologia Exp Applicata

Gassmann

et al. 2018

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The navel orangeworm, Amyelois transitella (Walker) (Lepidoptera: Pyralidae, Phycitini), is an economically important pest of nut crops in California, USA. Improved management will require better understanding of insect dispersal, particularly relative to when mating occurs. A previous study demonstrated a more robust laboratory flight capacity compared to other orchard moth pests, but it was unclear how mating affects dispersal, and how dispersal affects fecundity. In this study, 1-and 2-day-old females were allowed to fly overnight on a flight mill either before or after mating, respectively, and were then allowed to oviposit. Data on fecundity were compared between treatments to minimally handled or tethered-only control females. Females that mated before flight flew longer and covered a greater distance than those flying prior to mating. However, timing of flight relative to mating did not affect fecundity, nor did any measure of flight performance. There was no effect on fecundity when females were forced to fly for designated durations from 3 min to 2 h. Together, our data revealed no obvious trade-off between flight activity and reproductive output. Distances measured on the flight mills (mean ca. 15 km for mated females) may overestimate net displacement in the field where flight tracks are often meandering. The results suggest that most females mate and oviposit in or near their natal habitat, but that some may disperse potentially long distances to oviposit elsewhere. KeywordsAmyelois transitella, flight mills, dispersal, almonds, pistachios, Lepidoptera, Pyralidae RightsWorks produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted. Key words: Amyelois transitella, flight mills, dispersal, almonds, pistachios, Lepidoptera, Pyralidae AbstractThe navel orangeworm, Amyelois transitella (Walker) (Lepidoptera: Pyralidae, Phycitini), is an economically important pest of nut crops in California, USA. Improved management will require better understanding of insect dispersal, particularly relative to when mating occurs. A previous study demonstrated a more robust laboratory flight capacity compared to other orchard moth pests, but it was unclear how mating affects dispersal, and how dispersal affects fecundity. In this study, 1-and 2-day-old females were allowed to fly overnight on a flight mill either before or after mating, respectively, and were then allowed to oviposit. Data on fecundity were compared between treatments to minimally handled or tethered-only control females. Females that mated before flight flew longer and covered a greater distance than those flying prior to mating. However, timing of flight relative to mating did not affect fecundity, nor did any measure of flight performance. There was no effect on fecundity when females were forced to fly for designated durations from 3 min to 2 h. Together, our data revealed no obvious trade-off between flight activity and reproductive outp...

Impact of Trap Design and Density on Effectiveness of a Commercial Pheromone Lure for Monitoring Navel Orangeworm (Lepidoptera: Pyralidae)

Journal of Economic Entomology

Higbee²

2015

The navel orangeworm is an important pest of almonds, pistachios, and walnuts. A commercial pheromone lure for this pest became publicly available in 2013. We compared effectiveness of this synthetic lure (NOW Biolure) between common commercial trap designs, and with unmated females in wing traps. Orange wing traps and delta traps captured similar numbers of males when each was baited with females, although there was a significantly greater density of captured males on the smaller glue area of the delta traps. In contrast, lure-baited wing traps captured about half the males captured in female-baited wing traps in single-night tests. In these single-night tests, wing traps baited with NOW Biolure captured significantly more males than delta traps baited with NOW Biolure, and bucket traps and delta traps baited with NOW Biolure captured similar numbers of males. When the sampling interval was extended to a week, the performance of lure-baited and female-baited wing traps was more similar. Delta and bucket traps baited with NOW Biolure generally performed more poorly than wing traps baited with NOW Biolure in these weekly monitoring tests. However, the bucket traps occasionally outperformed the other trap types during periods of peak abundance. Navel orangeworm traps at a density of one per 4 ha detected differences in abundance between adjacent walnut varieties, whereas such differences were not detected with one trap per 20 ha. The implications of these findings for monitoring for navel orangeworm in these different host crops are discussed.