Plusiinae Species Research Articles

A Sex Attractant Synergist for Trichoplusia oxygramma (Lepidoptera: Noctuidae)

Trichoplusia oxygramma (Geyer) is closely related to the cabbage looper, Trichoplusia ni (Hubner), although it is not a pest species. Like many other Plusiinae, males are attracted in the field to traps baited with (Z)-7-dodecen-1-ol acetate (Z7-12:Ac), the major component of the sex pheromone of the female cabbage looper (Mitchell et al. 1972). During an experiment in which traps were baited with combinations of female cabbage looper sex pheromone components, T. oxygramma males were caught in traps baited with a combination of Z7-12:Ac and (Z)-9-tetradecen-1-ol acetate (Z9-14:Ac). We report here the result of a subsequent experiment demonstrating an increased sex attractant response by T. oxygramma males to Z7-12:Ac plus Z9-14:Ac compared to Z7-as:Ac alone, as indicated by trap catches. Plastic bucket traps (Universal moth trap, International Pheromones, Merseyside, England) were baited with two lures; a 1-mg dosage of Z7-12:Ac or a combination of 1-mg Z7-12:Ac and 90 ,ug Z9-14:Ac on a rubber septum. This ratio of 10 to 0.9 for Z7-12:Ac to Z9-14:Ac approximates the ratio of those components reported by Bjostad et al. (1984) for the female cabbage looper pheromone and is similar to the ratio in our original experiment in which T. oxygramma males were trapped. Septa were pre-extracted, handled and loaded as described by Landolt and Heath (1986). Traps were hung from shrubs about 1 m above ground level in uncultivated fields near Gainesville, Florida during Sept. and Oct. 1985. Traps were positioned as four treatment pairs with about 24m between paired traps. These were checked and septa switched daily between paired traps. Septa were replaced after 1 week. Treatment means were separated by Student's t-test at p > 0.05. Mean numbers of male T. oxygramma caught per week in traps baited with Z7-12:Ac plus Z9-14:Ac were significantly higher than in traps baited with Z7-12:Ac alone (Table 1), indicating a synergistic effect by Z9-14:Ac on the attractant response of male T. oxygramma to Z7-12:Ac. Although (Z)-9-14:Ac is a minor component of the sex pheromone of female T. ni (Bjostad et al. 1984), it did not have any synergistic effects on the response of T. ni males to Z7-as:Ac in a wind tunnel bioassay (Linn et al. 1984). Landolt and Heath (1986) also reported that numbers of male P. includens caught in traps were reduced greatly by the addition of Z9-14:Ac to Z7-12:Ac, indicating an inhibitory effect which may function in preventing interspecific courtship and mating between Trichoplusia spp. and P. includens. (Z)-9-Tetradecen-1-ol acetate also inhibits the attractant response (reduced trap catches) of two other species of Plusiinae, Autographa californica (Speyer) and A. flagellum (Walker), to Z7-12:Ac (Steck et al. 1979). Mention of a commercial or proprietary product does not constitute an endorsement by the USDA.

Sexual behaviour and pheromone titre in the tomato looper, Plusia chalcites (Esp.) (Lepidoptera: Noctuidae)

The sexual behaviour of Plusia chalcites (Esp.) was recorded in the laboratory and field. Females reached peak activity on the 4th night between 0.5–2 h into the scotophase. Maximal amounts of pheromone were found in the pheromone glands of 4–5-day old females. Male activity was monitored in a wind tunnel and peak activity was observed with 5–8-day old males, 1–4 h after the onset of the scotophase. Mating occurred 1–2 h after the beginning of the scotophase. In the field, sexual activity of both sexes was synchronized to the first 2 h of night and mating pairs were collected only during the first 3 h, although single females and males were present throughout the night. This timing of sexual behaviour is probably an important factor, in addition to pheromone specificity, in the sexual separation between P. chalcites and other, sympatric, Plusiinae species.

A CATALOGUE OF THE EGGS OF SOME CANADIAN NOCTUIDAE (LEPIDOPTERA)

AbstractPresented, with notes, are 124 plates of SEM illustrations of noctuid eggs representing 14 subfamilies of the Noctuidae: one species of Agaristinae, four species of Pantheinae, six species of Acronictinae, 34 species of Noctuinae, 26 species of Hadeninae, 10 species of Cuculliinae, 14 species of Amphipyrinae, three species of Acontiinae, two species of Euteliinae, two species of Plusiinae, 11 species of Catocalinae, one species of Hypeninae, one species of Rivulinae, and nine species of Herminiinae.

Sex Pheromone Components of the Gamma Moth, Autographa gamma (L.) (Lepidoptera: Noctuidae)

Z-7-Dodecenyl acetate and Z-7-dodecenyl alcohol have been identified as sex pheromone components o f female Autographa gamma. This is the first time that Z-7-dodecenyl alcohol has been found in the natural pheromone of Plusiinae. When incorporated in pherom one traps of some Plusiinae species the alcohol is both synergist and inhibitor, thus being an important factor in sex isolation among sympatric Plusiinae species in Israel

Looplure efficacy and electrophysiological responses in three plusiinae species

Source concentration differences of (Z)-7-dodecen-1-ol acetate, or looplure, were evaluated for field trapping efficiency and electrophysiological responses with malePseudoplusia includens (Walker),Trichoplusia ni (Hubner) andRachiplusia ou (Guenné) (Lepidoptera: Noctuidae). Sticky traps baited with 1000 μg of the lure captured a significantly greater (P < 0.05) number of maleP. includens andT. ni than any other concentration;R. ou males were caught at a greater rate in traps baited with 100 μg of looplure, significantly more (P < 0.05) than with 1000 μg. Electroantennogram (EAG) studies demonstrated that antennae of maleP. includens have a lower response threshold to looplure than eitherT. ni orR. ou antennae, the latter demonstrating the highest significant threshold of response. No differences in the stimulus-response functions of the three species were detected.

Sex pheromone of the tomato looper,Plusia chalcites (ESP)

Z-7-Dodecenyl acetate (A) andZ-9-tetradecenyl acetate (B), in a 5∶1 ratio, have been identified as sex pheromone components of femalePlusia chalcites. In addition, small amounts of dodecyl acetate, tetradecyl acetate, hexadecyl acetate, andZ-9-dodecenyl acetate have been found in the abdominal tip extracts. This is the first known Plusiinae species which utilizes a two-component primary sex pheromone system. The most effective lure found in field experiments was a mixture of 1 mg A and 0.2 mg B absorbed on rubber septa.

Parasitization of Two Species of Plusiinae 1 and Heliothis Spp. 1 After Releases of Trichogramma pretiosum2 in Seven Crops 3

Three releases (3 days apart) of Trichogramma pretiosum Riley at ca. 378,000/acre per release in a one-acre cage containing 7 crops resulted in substantial parasitism of eggs of the cabbage looper, Trichoplusia ni (Hubner), and in suppression of larvae of the cabbage looper in collards, cabbage, soybeans, bell peppers, and, particularly, tomatoes. Parasitism of eggs of the soybean looper, Pseudoplusia includens (Walker), was generally low in soybeans (and in other crops); possibly because the releases were not timed correctly for maximum effectiveness. Parasitism of eggs of Heliothis spp. [corn earworm, H. zea (Boddie), and tobacco budworm, H. virescens (F.)] was high in tomatoes and soybeans but was negligible in cigar-wrapper tobacco. Also, parasitism of eggs of 2 species of Plusiinae was low in tobacco. Generation cycling of the released parasites was indicated in crops where host egg densities remained at high levels for a sufficient period of time.

Relative Abundance and Host Preferences of Cabbage Looper, 1 Soybean Looper, 1 Tobacco Budworm, 1 and Corn Earworm 1 on Crops Grown in Northern Florida 2

The relative abundance and host plant preferences of cabbage looper, Trichoplusia ni (Hubner), soybean looper, Pseudoplusia includens (Walker), tobacco budworm, Heliothis virescens (F.), and corn earworm, Heliothis zea (Boddie), were studied in field cage and field experiments in Northern Florida. Results indicated relatively strong preferences of the test species for certain crops. Cabbage loopers were more abundant than soybean loopers and showed a strong preference for cabbage and collards over 21 other crops. Soybeans were the preferred host of the soybean looper, but substantial numbers of larvae were found on peanuts and tomatoes in the field. Both species readily oviposited on cockleburs in the presence of other host plants in a small field cage, and 4 other species of Plusiinae were found attacking crops in the field. Tobacco budworms were more abundant on tobacco and okra than on other crops in the field, and became abundant on okra only after tobacco was removed from the cropping system. Also, small numbers of tobacco budworm were found on cabbage, collards, peanuts, white clover, and tomatoes. In addition, substantial numbers of eggs and a few larvae were found on tomatoes in field cages. Corn earworms appeared to prefer corn, sorghum, and millet over other crops in the field, but infestations of this species were found on 18 of 21 crops tested. Also, a field cage test indicated that com earworms preferred tomatoes over other crops such as bell peppers, bush beans, cabbage, cigar-wrapper tobacco, collards, and soybeans.