Pseudaletia Unipuncta Research Articles

Seasonal Distribution of Fall Armyworm (Lepidoptera: Noctuidae) Host Strains in Agricultural and Turf Grass Habitats

Male fall armyworm moths [Spodoptera frugiperda (J. E. Smith)] were captured in pheromone traps over a 16- to 24-mo period in selected sites in southern Florida. Molecular markers were used to determine whether individuals were of one of two host strains (historically designated “rice-strain” and “corn-strain”). Traps placed in agricultural areas showed a population peak in the spring (March–May) and fall (October–December), with a prolonged decline in numbers in summer (July–October) and a smaller reduction in mid-winter (January). The host strain distribution during these periods varied significantly, suggesting strain-specific and seasonal population patterns. Both strains were captured in substantial numbers during the spring peak, but surprisingly, only the rice-strain showed an increase in capture rates during the fall, despite the presence of sweet corn throughout this period. Trap captures in a sod (turfgrass) farm were composed almost entirely of the rice-strain and showed a bimodal seasonal distribution similar to that seen in the agricultural areas, with peaks in the spring and fall. These results represent the first indication that the two host strains might have substantially different population dynamics in the overwintering agricultural areas of Florida and suggest that the rice-strain is the predominant fall armyworm pest during the fall and winter growing periods. It further indicates that the two strains can display a markedly different response to seasonal environmental cues. The implications of these findings on our understanding of fall armyworm migration are discussed.

Feeding responses of specialist herbivores to plant extracts and pure allelochemicals: effects of prolonged exposure

AbstractWe investigated the possibility of decreased feeding deterrent response following prolonged exposure in three specialist herbivores, Plutella xylostella (larvae), Pseudaletia unipuncta (larvae), and Epilachna varivestis (adults) through leaf disc choice and no‐choice tests. Neonate larvae (<24 h old) of the three species were reared on their host plants sprayed with the antifeedants until tested. Our results demonstrated that Ps. unipuncta did not show a decrease in feeding deterrent response to extracts of Melia volkensii (choice and no‐choice tests) or oregano (Origanum vulgare) (choice test) following prolonged exposure. Plutella xylostella exhibited a decrease in feeding deterrent response to M. volkensii in a choice test only, but not to oregano. Although not significant, we did find a trend toward decreasing feeding deterrent response to M. volkensii by both species in no‐choice tests. However, both species exhibited a significant decrease in feeding deterrent response to pure allelochemicals (Ps. unipuncta to thymol, and P. xylostella to thymol and toosendanin) compared with the naïve groups, following prolonged exposure in leaf disc choice tests. Epilachna varivestis showed a significant decrease in feeding deterrent responses to both oregano and thymol in leaf disc choice tests. We conclude from our present and previous studies that not only are there interspecific differences between generalist and specialist species but also among specialist species.

Effects of elevated atmospheric CO2 on the nutritional ecology of C3 and C4 grass-feeding caterpillars.

It is plausible that the nutritional quality of C3 plants will decline more under elevated atmospheric CO2 than will the nutritional quality of C4 plants, causing herbivorous insects to increase their feeding on C3 plants relative to C4 plants. We tested this hypothesis with a C3 and C4 grass and two caterpillar species with different diet breadths. Lolium multiflorum (C3) and Bouteloua curtipendula (C4) were grown in outdoor open top chambers at ambient (370 ppm) or elevated (740 ppm) CO2. Bioassays compared the performance and digestive efficiencies of Pseudaletia unipuncta (a grass-specialist noctuid) and Spodoptera frugiperda (a generalist noctuid). As expected, the nutritional quality of L. multiflorum changed to a greater extent than did that of B. curtipendula when grown in elevated CO2; levels of protein (considered growth limiting) declined in the C3 grass, while levels of carbohydrates (sugar, starch and fructan) increased. However, neither insect species increased its feeding rate on the C3 grass to compensate for its lower nutritional quality when grown in an elevated CO2 atmosphere. Consumption rates of P. unipuncta and S. frugiperda were higher on the C3 grass than the C4 grass, the opposite of the result expected for a compensatory response to the lower nutritional quality of the C4 grass. Although our results do not support the hypothesis that grass-specialist insects compensate for lower nutritional quality by increasing their consumption rates more than do generalist insects, the performance of the specialist was greater than that of the generalist on each grass species and at both CO2 levels. Mechanisms other than compensatory feeding, such as increased nutrient assimilation efficiency, appear to determine the relative performance of these herbivores. Our results also provide further evidence against the hypothesis that C4 grasses would be avoided by insect herbivores because a large fraction of their nutrients is unavailable to herbivores. Instead, our results are consistent with the hypothesis that C4 grasses are poorer host plants primarily because of their lower nutrient levels, higher fiber levels, and greater toughness.

Effect of Food Resources on Adult <I>Glyptapanteles militaris</I> and <I>Meteorus communis</I> (Hymenoptera: Braconidae), Parasitoids of <I>Pseudaletia unipuncta</I> (Lepidoptera: Noctuidae)

Adult parasitoids frequently require access to food and adequate microclimates to maximize host location and parasitization. Realized levels of parasitism in the field can be significantly influenced by the quantity and distribution of extra-host resources. Previous studies have demonstrated a significant effect of landscape structure on parasitism of the armyworm Pseudaletia unipuncta (Haworth) (Lepidoptera: Noctuidae). As a possible mechanism underlying this pattern, we investigated the effect of carbohydrate food sources on the longevity and fecundity of armyworm parasitoids under laboratory conditions of varying temperature, host availability, and mating status. Glyptapanteles militaris (Walsh) (Hymenoptera: Braconidae) adults lived significantly longer when provided with honey as food and when reared at 20°C versus 25°C. Meteorus communis (Cresson) (Hymenoptera: Braconidae) adults also lived significantly longer when provided with honey, although longevity was reduced when females were provided hosts. Honey-fed females of M. communis parasitized significantly more hosts because of their increased longevity, but did not differ in daily oviposition from females provided only water. Mating significantly increased parasitism by honey-fed M. communis, but not those provided water alone. These results indicate that the presence of both carbohydrate resources and moderated microclimates may significantly increase the life span and parasitism of these parasitoids. However, the greater longevity and lower daily rate of oviposition of M. communis suggest that food and microclimate resources are more critical for this species than for the shorter lived, gregarious G. militaris. These findings contribute to our understanding of how these two parasitoids respond to landscape complexity.

Comparative growth inhibitory and antifeedant effects of plant extracts and pure allelochemicals on four phytophagous insect species

Abstract:Antifeedant and growth inhibitory effects of crude plant extracts (Melia volkensii and Origanum vulgare) and pure allelochemicals (digitoxin, cymarin, xanthotoxin, toosendanin, thymol and trans‐anethole) were investigated in the cabbage looper (Trichoplusia ni), and in the armyworm (Pseudaletia unipuncta) using different bioassays. Antifeedant effects of M. volkensii, O. vulgare and thymol were investigated in larvae of the diamondback moth (Plutella xylostella), and of O. vulgare and thymol in the Mexican bean beetle (Epilachna varivestis), using leaf disc choice bioassays. M. volkensii was the most potent growth inhibitor for T. ni and P. unipuncta (dietary EC50 = 7.6 and 12.5 p.p.m., respectively) of all the test substances. Cymarin was the second most potent growth inhibitor (EC50 = 132.0 p.p.m.) for T. ni. The most effective feeding deterrents for third instar T. ni larvae were xanthotoxin andM. volkensii (DC50 = 0.9 and 8.3 μg/cm2, respectively). M. volkensii was also the most potent feeding deterrent for third instar P. unipuncta, P. xylostella and adult E. varivestis (DC50 = 10.5, 20.7 and 2.3 μg/cm2, respectively). Because of interspecific differences in response to feeding deterrents and the lack of a strong relationship between EC50 and DC50 values, we recommend testing a battery of bioassay species with candidate compounds and the use of more than one bioassay. Based on their growth inhibitory and feeding deterrent properties, some of these plant extracts and pure allelochemicals have potential for use as alternative crop protectants against a number of pest species.

AN EPIZOOTIC OF NUCLEAR POLYHEDROSIS VIRUS IN ARMYWORMS (PSEUDALETIA UNIPUNCTA) IN CONNECTICUT

An outbreak of armyworms, Pseudaletia unipuncta, occurred in widely separated sites in New England during the summer of 2001. Heavy mortality of caterpillars was noted in severely damaged suburban lawns and destroyed hayfields. Microscopic examinations of 90 moribund or recently expired caterpillars collected in Connecticut revealed a nuclear polyhedrosis virus (NPV) in 59 (66%) individuals from 5 of 6 sites. Virus development occurred in the nuclei and cytoplasm of the fat body. Based on ultrastructural studies, the NPV observed in Connecticut appears to be similar to a strain described earlier for armyworms in California and Hawaii.

An improved multi‐component sex attractant for trapping male western yellowstriped armyworm, Spodoptera praefica (Grote) (Lepidoptera: Noctuidae)

Abstract 1 Chemical analyses of solvent extracts of pheromone glands of female western yellowstriped armyworm moths Spodoptera praefica (Grote) indicated the presence of (Z)‐7‐dodecenol (Z)‐7‐dodecenyl acetate (Z)‐9‐dodecenyl acetate (Z)‐9‐tetradecenyl acetate and (Z)‐11‐hexadecenyl acetate.2 In field tests of combinations of these chemicals, small numbers of male S. praefica were captured in traps baited with (Z)‐7‐dodecenyl acetate. Numbers of males captured in traps were greatly increased in response to blends that included both (Z)‐7‐dodecenyl acetate with either (Z)‐9‐tetradecenyl acetate (Z)‐9‐dodecenyl acetate. The combination of (Z)‐7‐dodecenyl acetate and (Z)‐9‐tetradecenyl acetate provided the strongest sex attractant for use in trapping male S. praefica.3 Males of the cabbage looper Trichoplusia ni (Hübner) were captured in traps baited with blends possessing (Z)‐7‐dodecenyl acetate, and were greatly reduced in traps baited with blends that included (Z)‐7‐dodecenol.4 Multi‐component blends that included (Z)‐7‐dodecenol attracted males of the alfalfa looper Autographa californica (Speyer).5 Males of Peridroma saucia (Hübner) and Mamestra configurata Walker were captured in traps that included (Z)‐9‐tetradecenyl acetate with (Z)‐11‐hexadecenyl acetate.6 These responses by other species of moths to S. praefica pheromone components and blends may still complicate the use of any lure for S. praefica.

Sampling Plans for <I>Pseudaletia unipuncta</I> (Lepidoptera: Noctuidae) Larvae in Azorean Pastures

Abstract Pseudaletia unipuncta (Haworth) is a pest in Azorean pastures that causes up to 8% yield loss mainly during summer and early autumn. The objective of this research was to develop robust sampling plans based on larval spatial distribution. The number of larvae in three 60-m2 plots on S. Miguel Island (Azores) was determined. Plots of 0.25 m2 were the most accurate unit for estimating the population size. The relationship between mean and variance fitted both Taylor’s power law and Iwao’s patchiness regression model. Relationships to determine optimum sample sizes for fixed levels of precision based on both models were developed, but demanded a heavy sampling cost for the usual precision values (0.1–0.25). To reduce sampling effort, two sequential sampling plans were developed and compared, one based on Taylor’s parameters and the other based on Iwao’s parameters. For a precision of 0.25, Taylor’s sequential sampling plan led to an average 76% reduction of the sampling effort compared with sample s...

Evaluation of twenty-eight strains of Heterorhabditis bacteriophora isolated in Azores for biocontrol of the armyworm, Pseudaletia unipuncta (Lepidoptera: Noctuidae)

Abstract The armyworm, Pseudaletia unipuncta , is the most important pest in Azorean pastures. Although this pest has some parasitoids and pathogens, additional biological control agents are needed to manage it. Entomopathogenic nematodes, particularly Heterorhaditis bacteriophora , are good candidates because they have been isolated from pastures and crops in almost all islands of the Azorean Archipelago. We tested 28 Azorean isolates of H. bacteriophora in the laboratory against the 6th instar P. unipuncta to determine mortality rates and virulence of each isolate. Plot tests in the field were also conducted to evaluate the best time for application of the selected isolate. All isolates killed the larvae although important differences in the mortality rates were observed. Forty-eight h post exposure (HPE) to the nematode infective juvenile (IJ), insect mortality ranged from 0 to 92.5% and at 96 HPE, mortality ranged from 32.5 to 100%. Based on LC 50 and LT 50 , H. bacteriophora Az29 was the most pathogenic and the remaining 27 isolates were grouped in three classes of virulence. The most virulent class included four isolates with LC 50 ranging from 180 to 327 IJs/insect and LT 50 from 44 to 62.9 h. These isolates were obtained from three of the nine islands. High intrapopulational variability was detected on isolates in the moderately virulent class suggesting that these isolates are good candidates for genetic improvement. Field tests showed H. bacteriophora Az29 was more effective to control P. unipuncta larvae than Steinernema carpocapsae Az20 and H. bacteriophora Az32, belonging to the less virulent class. These tests also showed that applications performed during May resulted in better control than in July.

Differentiation and gene flow among island and mainland populations of the true armyworm,Pseudaletia unipuncta(Haworth) (Lepidoptera: Noctuidae)

The genetic structure of populations of the true armyworm, Pseudaletia unipuncta (Haworth) (Lepidoptera: Noctuidae), in the Azores archipelago was studied using polyacrylamide-gel electrophoresis. Four enzyme systems (aldehyde oxidase, esterase, phosphoglucomutase, and phosphoglucose isomerase) were examined in six populations from islands in the Azores (Santa Maria, São Miguel, Terceira, Pico, Faial, Flores) and compared with those from populations from mainland Portugal and Canada. The North American and European populations are not clearly separated from the Azorean ones. Similarly, studies of different enzyme systems (aldehyde oxidase, esterase, malic enzyme, sorbitol dehydrogenase, manose-6-phosphate isomerase, and phosphoglucomutase) over 2 years (1997 and 1998) at different times of the year (spring, summer, and autumn) and at three different altitudes (0, 250, and 500 m above sea level) on three different islands (Santa Maria, São Miguel, and Faial) uncovered no distinct differences. These results, obtained from classically used loci, suggest that there is still some gene flow between sites or that island populations have not been isolated for sufficient time to have diverged from founder populations.

Impact of True Armyworm (Lepidoptera: Noctuidae) Feeding on Wheat Yields in Arkansas

Wheat leaf consumption by the true armyworm, Pseudaletia unipuncta Haworth, was determined in the laboratory in 1993, 1994, and 1995. Total mean wheat leaf area consumed per larva from eclosion to pupation varied significantly from year to year (77.4–135.4 cm2) with an overall mean leaf area consumed of 103.2 cm2. Wheat field plots were infested with third-instar armyworms and allowed to consume wheat foliage at boot and anthesis stages until preset defoliation levels were met (0, 10, 25, and 50% defoliation in 1993, and 0, 35, 50, 65, and 75% defoliation in 1994, and 0, 35, 50, 65, and 75% defoliation in 1995, and 1996). Overall, no significant differences were seen between treatments in number of heads or mean weight of seeds per head in any year suggesting that at boot and anthesis stages Arkansas wheat can sustain up to 75% defoliation by armyworms with little loss in yield. Even at population levels that resulted in 75% defoliation head cutting was negligible.

Molecular characterisation of cDNAs from the fall armyworm Spodoptera frugiperda encoding Manduca sexta allatotropin and allatostatin preprohormone peptides

Allatotropin (AT) is a 13-residue amidated neuropeptide, first isolated from pharate adult heads of the tobacco hornworm, Manduca sexta (Manse-AT), which strongly stimulates the biosynthesis of juvenile hormones (JH) in the corpora allata (CA) of adult moths. In Spodoptera frugiperda, a cDNA that encodes 134 amino acids, including an AT peptide, has been cloned. The S. frugiperda allatotropin mature peptide (Spofr-AT) [GFKNVEMMTARGFa] is identical to that isolated from M. sexta. The basic organization of the Spofr-AT precursor is similar to that of Agrius convolvuli, M. sexta, Pseudaletia unipuncta, and Bombyx mori with 83–93% amino acid sequence identity. The Spofr-AT gene is expressed in at least three mRNA isoforms with 134, 171 and 200 amino acids, differing from each other by alternative splicing. All allatostatins (AS) have an inhibitory action on the JH biosynthesis in the CA. A cDNA that encodes 125 amino acid residues including one copy of the Manse-AS peptide has been cloned from S. frugiperda (Spofr-AS; QVRFRQCYFNPISCF). The basic organization of the Spofr-AS precursor is similar to that of P. unipuncta with 85% amino acid sequence identity. Using one step RT-PCR for semi-quantification of the gene expression, we showed that the three mRNAs of the Spofr-AT gene and the Spofr-AS gene are expressed in brains of last instar larvae, prepupae, pupae, and adults of both sexes of S. frugiperda with variable intensity.

Temporal variation in the response of parasitoids to agricultural landscape structure

Temporal variations in the relationship between agricultural landscape complexity and parasitoid abundance were assessed in Ingham County, MI. The study site consisted of a 3.2 km×13.9 km area including a complex and a simplified agricultural landscape. Landscape structure was quantified using black and white aerial photographs and digital land-use data. A heterogeneous mixture of crop and non-crop habitats characterized the complex landscape (40.6% of non-crop habitat), while the simple landscape was more uniform and contained less non-crop habitat (28.6%). In the complex landscape fields were 75% smaller, had 63% more perimeter of wooded field edge per hectare of field area, and 81% more field edge in wide hedgerow than in the simple landscape. In June–July 1993, 1996, 1998, 2000, and 2001, a total of 15,786 armyworm ( Pseudaletia unipuncta) larvae were released into maize fields. A total of 3752 larvae were recovered and reared in the laboratory with 1410 individuals parasitized by 15 identified species of parasitoids. Two species, Glyptapanteles militaris and Meteorus communis, represented 96.3% of the parasitoids recovered. Agricultural landscape structure influenced the temporal dynamics of P. unipuncta parasitism. While G. militaris was equally present in the simple (48.8% of total recovery) and complex landscape (51.2%), M. communis was found mostly in the complex landscape (78.9%). Overall, percentage parasitism differed between landscapes and among years with different trends in the simple and complex landscapes. These results indicate that effects of landscape structure on parasitism are not adequately characterized by short-term studies.

Effects of the Larval Diet ofPseudaletia unipuncta(Lepidoptera: Noctuidae) on the Performance of the ParasitoidGlyptapanteles militaris(Hymenoptera: Braconidae)

Abstract We evaluated preferences of the parasitoid Glyptapanteles militaris (Walsh) among various host-diet complexes in an effort to understand the abundance of the parasitoid in Azorean pastures. We also examined effects of host diet on the quality of the parasitoid as a biological control agent. The larvae of Pseudaletia unipuncta (Haworth) were reared on three different diets (Zea mays L., Lolium perenne L., and artificial diet) and were exposed to G. militaris. The percentage of parasitized larvae (yielding parasitoid cocoons), of host mortality unrelated to successful parasitism (host death without cocoon formation) and of pupating hosts did not differ significantly among diet treatments. Also, the total number of parasitoid larvae per host and the mean number of cocoons yielded per host did not differ significantly when hosts were fed on different diets. Time from egg to cocoon formation (16.1 and 18.6 d, respectively), pupal period (8.0 and 8.5 d, respectively), and total developmental time (24.1...

Enhanced infection of an entomopoxvirus in larvae of the armyworm, Pseudaletia separata (Lepidoptera: Noctuidae), by a granulovirus

To determine the interaction of Pseudaletia unipuncta granulovirus and Pseudaletia separata entomopoxvirus, larvae of the armyworm, P. separata, were perorally administered graded doses of entomopoxvirus occlusion bodies, spheroids, in the presence or absence of granulovirus occlusion bodies, capsules. The presence of capsules in the inocula enhanced entomopoxvirus infection. In doubly infected larvae, the inclusion bodies and virions of the two viruses coexisted in the same fatbody but never occurred in the same cells. The granulovirus appeared to facilitate entomopoxvirus infection at the organismal level, although the two viruses interfered with each other at the cellular level.

Enhanced haemolymph circulation by insect ventral nerve cord: hormonal control by Pseudaletia unipuncta allatotropin and serotonin.

The ventral diaphragm (VD) in many insects is a muscular membrane that essentially partitions a perineural sinus from the rest of the abdomen. In the true armyworm moth Pseudaletia unipuncta (Lepidoptera: Noctuidae) we describe how the VD is characterized by a series of aliform muscles inserted into a tissue matrix that is fused to the dorsal surface of the ventral nerve cord (VNC) itself. Because of this arrangement, the abdominal VNC can attain high rates of lateral oscillation, and is capable of directing haemolymph flow. We have previously demonstrated Manduca sexta allatotropin (Manse-AT)-like immunoreactivity throughout the central nervous system (CNS) in P. unipuncta, and that both Manse-AT and serotonin (5-HT) are dose-dependent stimulators of the dorsal vessel. Here we describe both Manse-AT- and 5-HT-like immunoreactivity associated with the VD. Furthermore, both Manse-AT and 5-HT are dose-dependent stimulators of the rates of VNC oscillation, and together are capable of maintaining highly elevated rates of VNC oscillation for extended periods of time. These data indicate that both the dorsal vessel and the VD/VNC are similarly modulated by both Manse-AT and 5-HT, and that VNC oscillations play a more active role in overall haemolymph circulation than previously recognized.

Insect Damage to Sweet Corn Hybrids in the South Atlantic European Coast

The pink stem borer (PSB) (Sesamia nonagrioides Lefebvre) and the European corn borer (ECB) (Ostrinia nubilalis Hübner) are the major insect pests of corn (Zea mays L.) in Mediterranean countries, although larvae of other insects can also cause damage. The objective of this research was to evaluate the effect of sweet corn hybrids, planting time, and environment on damage by various insects. Data were recorded on the number of larvae of each of the aforementioned pests and damage produced in the ear 20 days after pollination and in the ear and stem when plants were dry. PSB was the most abundant pest, followed by ECB. Other insects, such as Mythimna unipuncta (Haworth) and Helicoverpa armigera (Hübner) were rarely found in sweet corn plants. ECB was constant over time, PSB had larger seasonal variation, and M. unipuncta and H. armigera were highly variable over time. There were significant differences among planting dates and growing cycles for damage traits in each environment. Interactions among hybrids, planting dates, and environments were significant. Dry ears were damaged more than fresh ears and stems had more larvae than ears. The economic value of the crop was seriously affected because most fresh ears had some damage, and seed production would be severely affected by PSB.

Characterization and baculovirus-directed expression of a myosuppressin encoding cDNA from the true armyworm, Pseudaletia unipuncta

Insect myosuppressins are a highly conserved sub-family of peptides which are primarily characterized by the ability to suppress contraction of visceral muscles in a variety of insect species. We have isolated a cDNA from the true armyworm, Pseudaletia unipuncta, that encodes a prohormone containing a peptide identical to ManducaFLRFamide. We have shown that this myosuppressin gene appears to be expressed in late larval and adult insects. In Manduca sexta, a number of extended-FLRFamide peptides have previously been purified including ManducaFLRFamide, F7D (DPSFLRFamide), F7G (GNSFLRFamide) and two larger peptides F24 and F39 that contain the shorter ManducaFLRFamide sequence at their C-terminus. Comparison with the true armyworm prepropeptide characterized here identifies F24 and F39 as partially processed products from the same precursor. Expression in the true armyworm was shown by in situ hybridization to occur in over 150 cells throughout the adult brain and nerve cord, and also to occur in both open and closed endocrine type cells of the gut. Overexpression of the P. unipuncta FLRFamide cDNA from a baculovirus vector in cabbage looper caterpillars was used to assess the potential for myosuppressin expression as a means of enhancing virus efficacy. Viral expression of the armyworm prohormone cDNA resulted in raised levels of RFamide-like products in the hemolymph of infected insects, but the products were found to be chemically distinguishable from authentic mature peptide and probably represent partially processed hormone.

Cardioacceleratory effects of Manduca sexta allatotropin in the true armyworm moth, Pseudaletia unipuncta

Manduca sexta allatotropin (Manse-AT), a peptide originally isolated on the basis of its ability to stimulate juvenile hormone (JH) biosynthesis in the tobacco hornworm, is a potent in vitro stimulator of the corpora allata (CA) in Pseudaletia unipuncta (Lepidoptera: Noctuidae). At 10 −6M, Manse-AT stimulated in vitro rates of JH biosynthesis by CA of day 0 and 6 adult females 15- and 10-fold respectively. Both Manse-AT and serotonin were also shown to be dose-dependent stimulators of heart rate in day 0, 3 and 6 adult males and females. Furthermore, analysis suggests that there are differences in both resting and Manse-AT-stimulated heart rates depending on age and rearing conditions.

BOTH SEXES OF THE TRUE ARMYWORM (LEPIDOPTERA: NOCTUIDAE) TRAPPED WITH THE FEEDING ATTRACTANT COMPOSED OF ACETIC ACID AND 3-METHYL-1-BUTANOL

Male and female true armyworm moths, Pseudaletia unipuncta (Haworth), were captured in traps baited with the combination of acetic acid and 3-methyl-1-butanol and placed near fields of corn (Zea mays). In a comparison of these chemicals presented individually and together, significantly greater numbers of moths were captured in traps baited with acetic acid and 3-methyl-1-butanol, compared to traps baited with acetic acid alone or traps baited with 3-methyl-1-butanol alone. Eighty percent of the female true armyworm moths captured in September in traps baited with acetic acid and 3-methyl-1-butanol were unmated and immature (no eggs and with considerable fat body). The remaining 20% of those females captured were mated and had some ovarian development. These results demonstrate attraction of male and female true armyworm moths to the combination of acetic acid and 3-methyl-1-butanol and provide a new means of trapping females of this species.