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

Data are presented that demonstrate the responsiveness ofChrysopa carnea Stephens larvae to kairomones in the moth scales ofHeliothis zea (Boddie). Rates of predation byC. carnea on eggs ofH. zea were increased whenH. zea moth scales or a hexane extract of the scales was applied to the search area under laboratory and greenhouse conditions.Lepidoptera:NoctuidaeNeuroptera:ChrysopidaeIn 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 of this product 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. 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

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.     

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.     

Responses of braconid parasitoidsMicroplitis croceipes (Cresson) andM. demolitor Wilkinson to stereoisomers of kairomone 13-methylhentriacontane

The responses ofMicroplitis croceipes (Cresson) andMicroplitis demolitor Wilkinson to theR andS stereoisomers of the kairomone 13-meth-ylhentriacontane were evaluated. Singly and in combination at 5, 50-, and 500-ng dosage levels each were tested. There was a linear dosage response by both species to the three dosages. Furthermore, there was no difference between responses to the two stereoisomers or their combination by either species at any dosage level. The effects of the two stereoisomers were fully interchangeable and additive. This is the first report of parasitoid responses to stereoisomers of a kairomone.     

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.     

Beneficial arthropod behavior mediated by airborne semiochemicals

Odor-mediated host-searching by femaleMicroplitis croceipes, a braconid endoparasitoid of larvalHeliothis species, was studied in a flight tunnel. Volatiles emitted by third-instarH. zea feeding on cowpea seedling leaves were released and carried with the wind, resulting either in an irregularly shaped plume, or injected with high velocity, resulting in a conically shaped jet plume. Flight maneuvers ofM. croceipes had a higher stereotype in jet plumes compared to irregularly shaped plumes. Variation in odor concentration in jet plumes due to intermittent feeding of the host larvae did not affect the number of flights. At the levels employed, odor concentration did not alter the rate of upwind progress in jet plumes. Because air velocity inside a jet increases in the upwind direction,M. crocepies regulates its ground-speed during its approach to the odor source.     

Beneficial arthropod behavior mediated by airborne semiochemicals. II. Olfactometric studies of host location by the parasitoidMicroplitis croceipes (Cresson) (Hymenoptera: Braconidae)

The response ofMicroplitis croceipes (Cresson) to odors from a plant-host complex was investigated using a four-choice olfactometer. Female, but not male, parasitoids responded in a dose-dependent fashion to volatiles from the plant-host complex and oviposition experience enhanced this response. Female age had no apparent effect on the response. Both artificially damaged leaves and frass elicited positive responses but of lower magnitude than those elicited by the plant-host complex. Volatiles collected from the plant-host complex placed on filter paper also elicited positive responses by female parasitoids.Mention of a commercial or proprietary product does not constitute an endorsement by the USDA.     

Orientation ofMicroplitis croceipes (Hymenoptera: Braconidae) to green leaf volatiles: Dose-response curves

FemaleMicroplitis croceipes wasps were tested in a wind tunnel for their ability to orient to various concentrations of eight different green leaf volatile (GLV) substances [hexanal, (E)-2-hexenal, (E)-2-hexen-1-ol, (Z)-3-hexen-1-ol, (E)-2-hexenyl acetate, (Z)-3-hexenyl acetate, (Z)-3-hexenyl propionate, and (Z)-3-hexenyl butyrate]. Overall, the esters elicited the greatest percentage of successful orientation flights, the alcohols elicited an intermediate response, and the aldehydes elicited a low response. The semilog dose-response curves were generally hill-shaped with high responses at medium release rates and low responses at high or low release rates. For the aldehydes, positive responses occurred at all GLV release rates between 0.01 and 100 nl/min. For some alcohols and esters, positive responses occurred at release rates as low as 1 pl/min and as high as 1μl/min. These data show thatM. croceipes wasps are strongly attracted to GLVs and are capable of orienting to GLV concentrations that would occur in nature when a caterpillar feeds on a green leaf. Hence, in nature, GLVs may be important clues, enablingM. croceipes to locate their hosts.     

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.     

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.     

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     

Beneficial arthropod behavior mediated by airborne semiochemicals

Heliothis zea (Boddie) larvae fed cowpea seedlings produced volatile semiochemicals to whichMicroplitis demolitor Wilkinson responded in a wind tunnel. However, mostM. demolitor females reared fromH. zea larvae fed an artificial diet were not responsive at emergence to the same volatile semiochemicals. A preflight contact with frass fromH. zea fed cowpea was needed to stimulate a response of sustained flight in a wind tunnel. The most consistent flight response was 7–10 days postemergence. Response resulting from both antennal and ovipositor contact with host frass during preflight stimulation was no better than from antennal contact alone. Chilling the parasitoid pupae rendered most of the emerging females unresponsive to volatile semiochemicals.Hymenoptera: Braconidae.     

Behavioral and biological responses ofCotesia marginiventris to kairomones of the fall armyworm,Spodoptera frugiperda

Potential kairomone sources of the fall armyworm (FAW),Spodoptera frugiperda (J.E. Smith), were bioassayed with females ofCotesia marginiventris (Cresson) in Petri dishes (10 cm diam). MatedC. marginiventris females, ranging in age from 1 to 3 days exhibited the most intense bioassay responses to potential sources of kairomone. Contacting a FAW-damaged corn leaf modified the pattern of movement inC. marginiventris from random to one exhibiting a significant increase in klinokinesis. No significant differences were present in kairomone responses of nonconditioned and conditioned parasitoids and parasitoid response to kairomones did not change throughout the photophase (0800–1800 hr). Removal of one, both, or the first eight antennal segments reduced or eliminated the response of the parasitoid to kairomones. Female parasitoids did not exhibit a preference for corn leaves damaged by a particular fall armyworm instar and parasitization rates were highest in larvae 48 hr old.Submitted in partial fulfillment of the requirements for Doctor of Philosophy, Department of Entomology and Nematology, University of Florida, Gainesville.     

Effects of cotton condensed tannin,maysin (Corn) and pinitol (soybeans) onHeliothis zea growth and development

Maysin, a flavone glycoside from corn silks, inhibits ingestion, and thus growth, ofHeliothis zea (Boddie) larvae. Pinitol from soybeans inhibitedH. zea growth by the same mechanism. Despite the widely held assumption that tannins inhibit growth by inhibiting assimilation, cotton condensed tannin inhibitedH. zea growth by reducing ingestion; no evidence was found for a reduction in assimilation. Neonate larvae are shown to be much more sensitive to allelochemics than larvae that have fed on control diet before being transferred to diet containing plant allelochemics.Reference to a company and/or product named by the department is only for purposes of information and does not imply approval or recommendation of the product to the exclusion of others which may also be suitable.Published with the approval of the director of the Delaware Agricultural Experiment Station as Miscellaneous Paper No. 968, Contribution No. 514 of the Department of Entomology and Applied Ecology, University of Delaware, Newark, Delaware 19711.