Kairomones and their use for management of entomophagous insects

In laboratory experiments conducted to compare the kairomonal activity forMicroplitis croceipes (Cresson) of frass fromHeliothis zea (Boddie) larvae fed on different host plants,M. croceipes females responded to extracts of frass from larvae reared on cotton or soybeans but not on corn. The lack of response to frass from larvae reared on corn was shown to be a result of a lack of some appropriate chemical(s) in the corn.Lepidoptera: Noctuidae.Hymenoptera: Braconidae.In cooperation with the University of Georgia College of Agriculture Experiment Stations, Coastal Plain Station, Tifton, Georgia 31793. Accepted for publication February 9, 1981.Mention of a proprietary product in this paper does not constitute an endorsement by this product by the USDA.     

Kairomones and their use for management of entomophagous insects. XV.

Acids found in moth scales of laboratory-rearedHeliothis zea (Boddie) moths are hexanoic, heptanoic, octanoic, nonanoic, 2- (or 3-) furan carboxylic, phenylacetic, benzoic, sorbic, and 4-hydroxybenzoic acid. The last two of these acids are preservatives added to the artifical diet as sorbic acid and methyl-p-hydroxybenzoate. FemaleTrichogramma pretiosum Riley exhibited increased rates of parasitization ofH. zea eggs in the presence of some of these compounds in laboratory experiments. Exposure to a mixture of all of these compounds did not increase parasitization, and the elimination of acids from the crude moth-scale extract did not reduce parasitization by the wasps.Lepidoptera: Noctuidae.Hymenoptera: Trichogrammatidae.In cooperation with the University of Georgia College of Agriculture Experiment Stations, Coastal Plain Station, Tifton, Georgia 31793.Mention of a commercial or proprietary product in this paper does not constitute endorsement by the USDA.     

Kairomones and their use for management of entomophagous insects

A kairomone from adultHeliothis zea (Boddie) scales is an important factor in the host selection process ofTrichogrammapretiosum Riley. If the host density is sufficiently high (i.e., 1 egg/500 cm²) and higher), a complete coverage or solid treatment of kairomone spray may be the optimum for increasing parasitization rates, but this is not the case at lower host densities (e.g., 1 egg/2000 cm²). At the lower densities, the kairomone must be distributed in such a way as to retain the parasitoids in the target area without inhibiting their movement from one ovi-position site to the next. Simulated moth scale particles appear to fill this need since their density can be regulated to provide the optimum frequency of parasitoid stimulation and thus maximum rates of parasitization at prevailing host densities.Hymenoptera: Trichogrammatidae.In cooperation with the University of Georgia College of Agriculture Experiment Stations, Coastal Plain Station, Tifton, Georgia 31794. Accepted for publication November 21, 1978.Mention of a commercial or proprietary product in this paper does not constitute endorsement by the USDA.     

Kairomones and their use for management of entomophagous insects

Volatile chemicals emanating from an excretion (apparently meconium) and abdominal tips of femaleHeliothis zea (Boddie) moths mediated increased rates of parasitization ofH. zea eggs byTrichogramma pretiosum Riley. A blend of synthetic chemicals, consisting of hexadecanal, (Z)-7-hexadecenal, (Z)-9-hexadecenal, and (Z)-11-hexadecenal, which has been identified as the sex pheromone of and from the abdominal tip of femaleH. zea moths, also increased rates of parasitization ofH. zea eggs byT. pretiosum in greenhouse experiments. In addition, parasitization ofH. zea eggs by wildTrichogramma spp., in field plots of cotton,Gossypium hirsutum L., treated with a similar blend of chemicals, in Conrel fibers, was more than double that in untreated plots.Hymenoptera: Trichogrammatidae.Lepidoptera: Noctuidae.In cooperation with the University of Georgea College of Agriculture Experiment Stations, Coastal Plain Station, Tifton, Georgia 31793.Mention of a proprietary product does not constitute endorsement by the USDA.     

Kairomones and their use for management of entomophagous insects

The response ofTrichogramma pretiosum Riley to stimuli fromHeliothis zea (Boddie) and fromTrichoplusia ni (Hübner) was examined in the laboratory. Kairomones were responsible, at least in part, for the greater response to naturally depositedH. zea eggs.Hymenoptera: Trichogrammatidae.In cooperation with the University of Georgia College of Agriculture Experiment Stations, Coastal Plain Station, Tifton, GA 31794. Accepted for publication January 19, 1977.Mention of a commercial or proprietary product in this paper does not constitute endorsement by the USDA.     

Kairomones and their use for management of entomophagous insects: II. Mechanisms causing increase in rate of parasitization byTrichogramma spp.

When the effect of the kairomone, tricosane, on parasitization byTrichogramma achaeae Nagaraja and Nagarkatti of eggs ofHeliothis zea (Boddie) was studied in petri dish tests, the greatest percentage parasitization ( = 64%) was obtained if the entire filter paper was treated. Treatment of smaller areas (about the eggs) resulted in decreased parasitism. In the greenhouse, highest parasitization ( = 71%) byT. pretiosum (Riley) ofH. zea eggs placed on pea seedlings grown in pie pans was obtained if the whole pan was treated; lowest parasitism ( = 29%) occurred when the pans were untreated. Parasitization was intermediate ( = 52%) in other pans treated only at selected spots. Dissections ofH. zea eggs collected from kairomonetreated and untreated field plots revealed that eggs ofTrichogramma spp. were more efficiently distributed (less superparasitism) among host eggs in treated plots. These kairomones increase parasitization ofTrichogramma spp. by releasing and continuously reinforcing an intensified searching behavior rather than by attracting and guiding the parasite directly to the host.Hymenoptera: Trichogrammatidae.In cooperation with the University of Georgia College of Agriculture Experiment Station, Coastal Plain Station, Tifton, Georgia.Mention of a proprietary product in this paper does not constitute an endorsement of this product by the USDA.     

Kairomones and their use for management of entomophagous insects: X. Laboratory studies on manipulation of host-finding behavior ofTrichogramma pretiosum riley1 with a kairomone extracted fromHeliothis zea (boddie) moth scales

The behavioral response ofTrichogramma pretiosum Riley females to the kairomone found inHeliothis zea (Boddie) moth scales is examined.Hymenoptera: Trichogrammatidae.In cooperation with the University of Georgia College of Agriculture Experiment Stations, Coastal Plain Station, Tifton, Georgia 31793.Mention of a proprietary product in this paper does not constitute an endorsement of this product by the USDA.The authors would like to acknowledge the excellent technical assistance of Mrs. Marcella Latham.     

Kairomones and their use for management of entomophagous insects VIII. Effect of diet on the kairomonal activity of frass fromHeliothis zea (Boddie) larvae forMicroplitis croceipes (Cresson)

Heliothis zea (Boddie) larvae were reared on fresh plant material (cowpea cotyledons) or on an artificial laboratory diet. Effect of these two diets on the kairomonal activity of the frass and cuticle from the larvae, as well as the kairomonal activity of the diets themselves, forMicroplitis croceipes (Cresson) was determined. Diet was found to significantly affect the kairomonal activity of the frass although the diets themselves were not active.Lepidoptera: Noctuidae.Hymenoptera: Braconidae.Part of the work reported here was done as a high school science project. This project was awarded the Grand Award in Life Sciences at the 29th and 30th Georgia Science and Engineering Fair, April 1977 and 1978, respectively; the Fourth Place Award in Zoology at the International Science and Engineering Fair held in Cleveland, Ohio, May 1977; the Second Place Award in Zoology at the International Science and Engineering Fair held in Anaheim, California, May 1978; and received other special awards.In cooperation with the University of Georgia College of Agriculture Experiment Stations, Coastal Plain Station, Tifton, Georgia 31794.Mention of a commercial or proprietary product in this paper does not constitute endorsement by the USDA.     

Kairomones and their use for management of entomophagous insects

Telenomus remits Nixon is a parasitoid that attacks egg masses ofSpodoptera frugiperda (J.E. Smith). Increased host-seeking behavior was elicited fromT. remus females in Y-tubes, Petri dish, and greenhouse bioassays byS. frugiperda female abdominal tips as well as (Z)-9-tetradecene-1-ol acetate and (Z)-9-dodecene-1-ol acetate.     

Kairomones and their use for management of entomophagous insects. IV. Effect of kairomones on productivity and longevity ofTrichogmmma pretiosum riley (Hymenoptera: Trichogrammatidae)

Kairomones in the scales ofHeliothis zea (Boddie) increased the percent parasitization, the number of progeny produced, and the longevity of femaleTrichogramma pretiosum Riley.In cooperation with the University of Georgia College of Agriculture Experiment Station, Coastal Plain Station, Tifton, Georgia 31794.Mention of a commercial or proprietary product in this paper does not constitute endorsement by the USDA.     

Field evaluation of herbivore-induced plant volatiles as attractants for beneficial insects: methyl salicylate and the green lacewing,Chrysopa nigricornis

Synthetic methyl salicylate (MeSA), a herbivore-induced plant volatile (HIPV), was demonstrated to be an attractant for the green lacewing, Chrysopa nigricornis, in two field experiments conducted in a Washington hop yard. Significantly greater numbers of C. nigricornis were trapped on MeSA-baited sticky cards (mean: 2.8 ± 0.4/card/week) than on unbaited cards (0.45 ± 0.15) during June–September. Cards baited with two other HIPVs, hexenyl acetate and dimethyl nonatriene, did not attract more C. nigricornis than did unbaited traps (0.30 ± 0.10, 0.44 ± 0.15, respectively). MeSA-baited Unitraps captured 1.9 ± 0.5 C. nigricornis/trap/week during July–August compared to 0.20 ± 0.20/trap/week in methyl eugenol-baited traps and 0.03 ± 0.03/trap/week in unbaited traps. The potential use of MeSA in enhancing C. nigricornis populations in Washington hop yards as an aid to conservation biological control of aphids and mites is discussed.     

Kairomones and their use for management of entomophagous insects: I. Evaluation for increasing rates of parasitization byTrichogramma spp. in the field

Kairomones forTrichogramma spp. were evaluated in the field on soybeans and crimson clover. Blanket (complete coverage) spraying of plots (either a synthetic tricosane or an eluate from a hexane extract of moth scales, depending on the responsiveness of theTrichogramma spp. present) resulted in increased parasitization by released and wildTrichogramma populations. The increased parasitization resulted for both natural and artificially applied eggs.     

Semiochemicals for use with parasitoids: Status and future

Allelochemicals are known to serve important roles at all steps in the host-searching sequence of parasitoids. We discuss the various roles of these allelochemics and the type of information needed to develop their use in pest control, which to date has been very limited. Rapid advancements are being made with respect to airborne chemicals and longer-range foraging behavior. Moreover, recent discoveries have shown that genetic diversity in parasitoid populations and phenotypic plasticity of individuals, together with their physiological state, often result in substantial variations in the response to chemical cues. Successful application of semiochemical-parasitoid systems will require management of these intrinsic parasitoid variables as well as management of the foraging environment. We illustrate emerging technology for such an application. For the immediate future, the development of this technology will allow us to: (1) define the genetic and phenotypic foraging profiles important to consistent and efficient parasitoid foraging, and (2) establish the proper propagation and release procedures and monitoring bioassays necessary to ensure appropriate behavioral and physiological qualities of released organisms. For the long term, we envision technology for comprehensively manipulating the pest/crop environment in ways that would provide foraging stimuli and other needs important to retention and efficiency of parasitoids.     

Plants—the origin of kairomones utilized by parasitoids of phytophagous insects?

Chemicals previously identified as kairomones utilized by parasitoids have been found in significant quantities in food plants of host insects. Different plant species contain varying concentrations and ratios of these chemicals. Feeding studies with chemically labeled kairomones indicate that these cues are concentrated and released unaltered by the host insect. In this report, a theoretical framework consistent with these findings is considered.     

Quantitative comparison of behavioral and neurophysiological responses of insects to odorants

A consistent pattern of relationships emerges from comparisons of insect electroantennograms, peripheral olfactory receptor neuron responses, and behavioral responses to quantified concentrations of odorants. One consistency is that all of the different response measurements can be described by stimulus-response curves of the same form. Another is that the responses have characteristic groupings when they are plotted against odorant concentration. The pattern of relationships is exemplified in the responses ofTrichoplusia ni (Hübner),Heliothis zea (Boddie), andPlodia interpunctella (Hübner) to several pheromone components and analogs. To quantify the relevant stimulus parameters for the response comparisons, the emission rates of the stimulus delivery system were calibrated for several 12 to 17-carbon pheromone components. The stimulus-response relationships determined forT. ni, H. zea, andP. interpunctella are combined with relationships reported for other insects in the literature, and applications are discussed for the interpretation of pheromone trapping and laboratory bioassays.Postdoctoral fellow employed through a cooperative agreement between the Insect Attractants, Behavior, and Basic Biology Research Laboratory     

Kairomones Used by Trichogramma chilonis to Find Helicoverpa assulta Eggs

Chemically mediated interactions between an egg parasitoid, Trichogramma chilonis, and its host insect, Helicoverpa assulta, were studied in laboratory experiments. T. chilonis was attracted to the sex pheromone of H. assulta, and, among four components of its sex pheromone, (Z)-11-hexadecenyl acetate seemed to be most attractive. T. chilonis was also highly attracted to (E)-12-tetradecenyl acetate, a component of the sex pheromone of Ostrinia furnacalis, another host. H. assulta eggs were more parasitized by T. chilonis when the eggs were treated with male moth scale extract (MSE) of H. assulta. Parasitism was also affected by the age of the parasitoid, time of day, and MSE concentration. Silica gel chromatography and subsequent argentation chromatography for MSE fractionation indicated the activity was associated with the fraction of saturated hydrocarbons. A linear olfactometer experiment revealed that H. assulta eggs also contain a short-range attractant(s).     

Effects of pheromone components and their degradation products on the response ofHeliothis spp. to traps

None of the isolated degradation products of (Z)-11-hexadecenal [(Z)-11-HDAL] affected the catches of either tobacco budworm [Heliothis virescens (F.)] or bollworm [H. zea (Boddie)] moths when dispensed with pheromone from cotton dental rolls in cone traps. Also, none of the degradation products of (Z)-9-tetradecenal [(Z)-9-TDAL] had an effect on trap catches of tobacco budworm moths. Two of the three chemicals that have previously been identified in ovipositor washes of tobacco budworms but that are absent in those of bollworms caused a reduction in capture of bollworms: (Z)-9-TDAL (1.0 g/trap) caused a 96% reduction in trap catch and (Z)-11-hexadecen-1-ol (20.0 g/trap) caused a similar reduction. Tetradencenal (40 g/trap) had no effect on trap catch.In cooperation with the Texas Agricultural Experiment Station, Texas A&M University, College Station, Texas 77843.This paper reports the results of research only. Mention of a pesticide in this paper does not constitute a recommendation for use by the USDA nor does it imply registration under FIFRA as amended. Also, mention of a commercial or proprietary product in this paper does not constitute an endorsement of this product by the USDA.     

Kairomones and their use for management of entomophagous insects: III. Stimulation ofTrichogramma achaeae,T. pretiosum,andMicroplitis croceipes with host-seeking stimuli at time of release to improve their efficiency

Frass from larvae of the corn earworm,Heliothis zea (Boddie) and scales fromH. zea moths (that are known to contain the host-seeking stimulus, tricosane) stimulate and orient host-seeking activity in femaleMicroplitis croceipes (Cresson), a larval parasite ofH. zea, andTrichogramma spp., egg parasites ofH. zea. When larval frass, moth scales, and tricosane were used as sign stimuli (releasers) forM. croceipes, T. pretiosum (Riley), andT. achaeae Nagaraji and Nagarkatti, respectively, at time of their release from laboratory containers, parasite performance improved, resulting in significantly increased rates of parasitization over that of unstimulated parasites. Stimulation ofM. croceipes with larval frass had an overriding effect on this parasite's innate tendency to disperse upon release, thereby increasing the numbers remaining and prolonging their retention in the target area. Supplying the appropriate host-seeking stimuli to these 3 hymenopterous parasites ofH. zea at time of their release to improve their efficiency greatly increases the probability of their effective utilization in pest management systems.     

Sex pheromone specificity inHeliothis

Electric grid traps baited withHeliothis subflexa (Guenée),H. virescens (F.), orH. zea (Boddie) females captured conspecific males with few exceptions.Heliothis subflexa females reduced the attraction ofH. virescens andH. zea males when used as bait simultaneously with females of either of these two species. Backcrosses were made withH. virescens males and female hybrids from a cross betweenH. subflexa females andH. virescens males. The backcross (BC) females andH. virescens females attracted approximately equal numbers ofH. virescens males in field traps. BC males released in field cages were attracted toH. virescens females and to the synthetic pheromone ofH. virescens. When laboratory-reared maleH. virescens, BC males,H. subflexa males, and F₁ hybrid males were exposed to the synthetic pheromone ofH. virescens in Plexiglas wind tunnels,H. virescens males and BC males responded to the pheromone, butH. subflexa and F₁ hybrid males did not. The peak activity of bothH. subflexa andH. zea males occurred approx. 4 hr after sunset. MaleH. zea were active throughout most of the night; maleH. virescens were most active approx. 6 hr after sunset.This paper reports the results of research only. Mention of a pesticide or of a commercial or proprietary product in this paper does not constitute a recommendation for use by the U.S. Department of Agriculture nor does it imply registration under FIFRA as amended.Lepidoptera: Noctuidae.     

Kairomones for the egg parasiteTrichogramma evanescens Westwood

In observation-cage experiments some new contact kairomones for the egg parasiteTrichogramma evanescens Westwood are demonstrated.T. evanescens females search significantly longer on cabbage leaves treated with the wing scales of two hosts,Pieris brassicae L. andP. rapae L. Further, egg washes ofP. brassicae containing an oviposition deterrent pheromone for the butterflies, were found to have a contact-kairomonal effect on the parasite.T. evanescens females search significantly longer on cabbage leaves sprayed with a methanol or water wash ofP. brassicae eggs than on leaves treated with the solvent only.Hymenoptera: Trichogrammatidae.Lepidoptera: Pieridae.