The Future of Organic Insect Pest Management: Be a Better Entomologist or Pay for Someone Who Is

Insect pest management in certified organic production systems presents considerable challenges for growers. The Federal National Organic Program (NOP) guidelines list acceptable tactics, but their effective use requires a considerable knowledgebase in entomology. The range of tactics allowed by the NOP are viewed as limiting by many growers and there are important elements missing from the list such as pest monitoring and identification. Educational programs must consider utilizing instructional methods and additional means of outreach that introduce new pest management tactics that are individualized, regionally appropriate and emphasize grower adoption and collaboration with local professionals. This review describes the challenges and knowledge burden associated with the listed NOP pest management guidelines, provides an educational model that includes an additional level of professional support for enhanced adoption of novel pest management tactics, or refinement of current practices, with a special emphasis on the importance of insect pest population monitoring

Life History of Paracantha gentilis (Diptera: Tephritidae)

The life history of Paracantha gentilis Hering in southern California is described. This stenophagous tephritid reproduces in the capitula of native Cirsium thistles. Courtship and mating behavior are described from field and laboratory observations. Territorial and courtship behavior of males and the morphological characters involved in possible male pheromone emission are described and illustrated, as are the oviposition behavior and reproductive morphology of females. Egg clutch sizes ranged from one to 13 eggs, with a maximum of six clutches per capitulum. Larvae fed gregariously within stage-specific niches. Pupariation occurred in the capitula, from which adults emerged in mid-June through early July. After emergence, most adults probably disperse to higher elevations to feed until autumn, then return to lower elevations and reproduce the following year. Limited reproduction also occurs in late-formed capitula or in capitula of alternate Cirsium hosts

Biology and parasitism rates of Pteromalus nr. myopitae (Hymenoptera: Pteromalidae), a newly discovered parasitoid of olive fruit fly Bactrocera oleae (Diptera: Tephritidae) in coastal California

An undescribed wasp, Pteromalus nr. myopitae (Hymenoptera: Pteromalidae) opportunistically parasitizes the olive fruit fly Bactrocera oleae (Rossi) (Diptera: Tephritidae), an introduced pest of olives in California. The native or typical host of P. nr. myopitae is unknown. We demonstrate that P. nr. myopitae is a solitary, ectoparasitic, idiobiont parasitoid of the third instar host inside fruit, and pupation occurs in the host tunnel. Reproduction of P. nr. myopitae on B. oleae in olives in the laboratory and in field cages generally failed. Host-feeding was not observed, and adults fed honey and water lived longer than those provided with water alone. Parasitism in non-commercial olives in the moderate coastal climate of San Luis Obispo occurred primarily from August to October, and was absent from a nearby location with more extreme climate and a low population of B. oleae. Greater parasitoid numbers were associated with greater host densities, and proportion of hosts parasitized was generally higher at lower host densities during 2 years of the study. The geographic range of the parasitoid extends along the coast from San Francisco Bay to Ensenada, Baja California, Mexico, and also inland in the Sacramento Valley, with one record in the San Joaquin Valley. The potential of the parasitoid as a biological control agent of B. oleae is probably low, however, the extent of its interference with other parasitoids being considered for release in California is unknown and warrants further study

Comparative Biologies of the Cryptic, Sympatric Species, Trupanea bisetosa and T. nigricornis (Diptera: Tephritidae) in Southern California

The biologies of the sympatric, cryptic species, Trupanea nigricornis (Coquillett), a flower head-infesting fruit fly attacking a wide range of hosts in 8 tribes, 33 genera, and at least 71 species of Asteraceae, and T. bisetosa (Coquillett), an oligophage attacking only 6 hosts in 4 genera of the tribe Heliantheae, are described and compared. A major biological distinction between these species was their ovipositional behavior, whereby females oviposited different numbers of eggs at different sites in different developmental stages of flower heads of their hosts. The larvae of these species showed minor differences in their feeding behaviors, and their puparia were formed and located similarly in host flower heads. Development from egg to adult under field conditions lasted up to 35 d for each species. These species showed subtle differences in their courtship and mating behaviors, and substantial differences in the daily timing of courtship

Behavior of Female Eretmocerus sp. nr. Californicus Howard (Aphelinidae: Hymenoptera) Attacking Bemisa Argentifolii Bellows and Perring (Aleyrodidae: Homoptera) on Two Native Californian Weeds

Searching and ovipositional behaviors by female Eretmocems sp. nr. californicus Howard on Bemisia argentifolii Bellows and Perring infesting velvetleaf, Abutilon theophrasti Medic. (Malavaceae), and telegraph weed, Heterotheca grandiflora Nutt. (Asteraceae), were quantified. Adult female behaviors were described and quantified for E. sp. nr. californicus to establish a behavioral time budget analysis. Females departed from leaves of A. theophrasti in 83.3% of the trials, and of those that remained and searched for hosts, walking speeds averaged 0.29 mm/s. Females departed from the leaves of H. grandiflora in 44.4% of the trials, and those remaining readily searched for whitefly hosts with walking speeds averaging 0.26 mm/s. The duration of host assessment by antennation was related to subsequent behaviors; rejecting a host was a shorter process than accepting it for further evaluation irrespective of plant species or nymphal stage. Evidence for a behavioral preference for oviposition under early nymphal instars was documented for female E. sp. nr. californicus on both plant species. Oviposition efficiency in 1-h laboratory trials for nymphs on A. theophrasti was 30% and efficiency on H. grandiflora was 23%. Females spent 61.9 and 53.3% of their total time in searching, host assessment, probing, and oviposition while on A. theophrasti and H. grandiflora, respectively. The remainder of the time was spent grooming, resting, and host feeding, except host feeding on A. theophrasti was not observed. Implications of this study for silverleaf whitefly management through conservation and augmentation of native flora and fauna are discussed

Host-Plant Effects on the Behavior of Eretmocerus sp. nr. Californicus Females Raised from Melon

The behaviors of female Eretmocerus sp. nr. californiens raised from Bemisia argentifolii Bellows & Perring on melon, Cucumis melo L., were analysed on four different host plant species (cotton, melon, sweet potato and Abutilon theophrasti Medic). Comparison with previously published results of similarly treated females reared from sweet potato plants showed performance related differences leading to oviposition. In the present study, the generalized behavioral pathway (walking, host- encounter, antennation, probing and oviposition) did not vary among host plant species for melon- reared parasitoid females. Host assessment by antennation leading to host acceptance for probing varied from 10.5- 12.3 sec among the host plant species with no host stage- related differences in duration. Initial and repeated (multiple probes on the same host nymph) probing events varied from 52.4 to 77.3 sec among host plant species and no stage- related differences were detected. Oviposition occurred under 62 % of the nymphs on cotton, 100 % of the nymphs on melon and 51 % of the nymphs on sweet potato under which the ovipositor was exserted. On cotton, melon and sweet potato proportionally fewer first instar nymphs were encountered than present, a larger proportion of the second instars that were encountered were subsequently antennated, and a larger proportion of second instars on cotton were then subsequently probed. For cotton, melon, and sweet potato, the overall frequency of oviposition was lower than reported in previous studies. Results from these studies showed that the greatest factor in influencing overall parasitism in laboratory experiments was the propensity of females to alight and remain to search for hosts on a particular host plant. The role of “pre- conditioning” parasitoids to be better- suited to a particular host or host plant species is discussed relative to the findings herein

Off-Shell Interactions for Closed-String Tachyons

Off-shell interactions for localized closed-string tachyons in C/Z_N superstring backgrounds are analyzed and a conjecture for the effective height of the tachyon potential is elaborated. At large N, some of the relevant tachyons are nearly massless and their interactions can be deduced from the S-matrix. The cubic interactions between these tachyons and the massless fields are computed in a closed form using orbifold CFT techniques. The cubic interaction between nearly-massless tachyons with different charges is shown to vanish and thus condensation of one tachyon does not source the others. It is shown that to leading order in N, the quartic contact interaction vanishes and the massless exchanges completely account for the four point scattering amplitude. This indicates that it is necessary to go beyond quartic interactions or to include other fields to test the conjecture for the height of the tachyon potential.Comment: 37 pages, 3 figures, LaTeX, JHEP class. Typos corrected, references added, published versio