Gary L. DeBarr

Pheromones in white pine cone beetle, Conophthorus coniperda (Schwarz) (Coleoptera: Scolytidae)

Female white pine cone beetles,Conophthorus coniperda, attacking second-year cones of eastern white pine,Pinus strobus L., produced a sex-specific pheromone that attracted conspecific males in laboratory bioassays and to field traps. Beetle response was enhanced by host monoterpenes. The female-produced compound was identified in volatiles collected on Porapak Q and in hindgut extracts as (+)-trans-pityol, (2R,5S)-(+)-2-(1-hydroxy-1-methylethyl)-5-methyltetrahydrofuran. Males and females produced and released the (E)-(-)-spiroacetal, (5S,7S)-(-)-7-methyl-1,6-dioxaspiro[4.5]decane, which was not an attractant for either sex, but acted as a repellent for males. Porapak Q-trapped volatiles from both sexes contained (+)-trans-pinocarveol and (-)-myrtenol. In addition, hindgut extracts of females containedtrans-verbenol, while males had pinocarvone and verbenone. Work in Georgia and Canada confirmed that the same isomers of pityol and spiroacetal are present in two distinct and widely separated populations ofC. coniperda.

Factors affecting capture of the white pine cone beetle, Conophthorus coniperda (Schwarz) (Col., Scolytidae) in pheromone traps

Abstract: The white pine cone beetle, Conophthorus coniperda, is a serious pest of seed orchards. The sex pheromone (+)‐trans‐pityol, (2R,5S)‐2‐(1‐hydroxy‐1‐methylethyl)‐5‐methyltetrahydrofuran, shows considerable promise to manage the cone beetle populations in seed orchards. Our work confirms that pityol is an effective attractant to capture male C. coniperda. Traps need to be placed in the tree crown, preferably in the cone‐bearing region, to trap out more insects. Japanese beetle traps were superior to the Lindgren funnel traps in capturing insects and trap colour had no significant effect. Commercially available bubble caps for dispensing pheromone were as effective as the experimental ‘vial and wick’ and the glass capillary tube units. Pityol released at about 0.1 mg ṁ day−1 (100 female equivalents) was effective, and higher (more expensive) rates did not significantly improve trap catch.

Dose and enantiospecific responses of white pine cone beetles, Conophthorus coniperda, to α-pinene in an eastern white pine seed orchard

The white pine cone beetle, Conophthorus coniperda, exhibited dose and enantiospecific responses to α-pinene in stands of mature eastern white pine, Pinus strobus, in a seed orchard near Murphy, North Carolina, USA. (−)-α-Pinene significantly increased catches of cone beetles to traps baited with (± )-trans-pityol. (+)-α-Pinene did not increase catches of beetles to pityol-baited traps and interrupted the response of beetles to traps baited with (±)-trans-pityol and (−)-α-pinene. Maximal attraction of cone beetles to pityol-baited traps was obtained with lures releasing (−)-α-pinene at a rate of 103 mg/day at 23°C. Lures releasing (−)-α-pinene at rates lower or higher than 103 mg/day resulted in reduced catches to traps baited with (±)-trans-pityol. The sex ratio in all catches was heavily male biased. Attraction of the clerid predator, Thanasimus dubius, to traps baited with (±)-trans-pityol increased significantly with the presence of α-pinene, irrespective of enantiomeric composition. Maximal attraction of T. dubius to pityol-baited traps occurred with devices releasing (−)-α-pinene at the highest rate tested, 579 mg/d at 23°C, a sub optimal rate for cone beetles.

Impacts of Red Imported Fire Ants (Hymenoptera: Formicidae) on Striped Pine Scale (Homoptera: Coccidae) Populations

Loblolly pines, Pinus taeda L., were banded in three seed orchards in Georgia to prevent the red imported fire ant, Solenopsis invicta (Buren), from tending infestations of striped pine scales, Toumeyella pini (King). Ant activity had no effect on female scale insect survival as numbers per shoot were never significantly different between check and banded trees in any of the orchards. Parasitism of females rarely differed between treatments, with higher rates twice in one orchard on unbanded trees and once in another orchard on banded trees. There also appeared to be no treatment effects on predator numbers. Coincident populations of the mealybug Oracella acuta (Lobdell) and the woolly pine scale, Pseudophilippia quaintancii Cockerell, on the shoots also were unaffected by the presence of fire ants.

LIFE HISTORY OF THE WOOLLY PINE SCALE PSEUDOPHILIPPIA QUAINTANCII COCKERELL (HOMOPTERA: COCCIDAE) IN LOBLOLLY PINE SEED ORCHARDS

The woolly pine scale, Pseudophilippia quaintancii Cockerell, had 2 generations per year in the Georgia coastal plain. Crawler activity peaked in late March-early April and late May to mid-June. First-generation males were wingless and emergence began in late April. Second-generation males were alate and their emergence peaked in early July. Populations of P. quaintancii increased during the first generation and dispersal occurred during the second. Fecundity averaged about 500 offspring per female. Populations were significantly affected by tree clone and crown level, with higher average survival in the upper crown. Parasitism of the woolly pine scale was low.

WITHIN-CROWN DISTRIBUTION OF CONE AND SEED INSECT DAMAGE TO SLASH PINE FLOWERS, CONELETS, AND CONES

From 76 to 87% of the total cone crop was located in the upper half of the tree crowns of slash pines, Pinus elliottii Engelm. var. elliottii, in Baker County, Florida. The east and south quadrants supported significantly larger crops than the north and west quadrants. The numbers of female strobili attacked by the slash pine flower thrips, Gnophothrips fuscus; cone-worms, Dioryctria spp.; or seedworms, Laspeyresia spp., did not differ significantly among the quadrants. Significantly greater numbers and percentages of cones in the upper crown were infested by Dioryctria spp. More cones in the upper crown were infested by Laspeyresia spp., but the percentage of cones infested, as well as the average number of Laspeyresia larvae per cone, did not vary significantly between levels or among quadrants. The proportion of full, empty, and seedbug damaged seed did not differ significantly among quadrants or crown levels.

(3Z,6Z,9Z,12Z,15Z)-Pentacosapentane and (9Z, 11E)-Tetradecadienyl Acetate: Attractant Lure Blend for Dioryctria ebeli (Lepidopterea: Pyralidae)

Feeding damage by larval coneworms (Lepidoptera: Pyralidae) on flowers and cones of pines can cause significant economic losses in pine seed orchards in the southern USA (Ebel et al. 1980, USDA Forest Service GTR SE-8, Asheville, NC). The south coastal coneworm, Dioryctria ebeli Mutuura & Monroe, is a common pest in seed orchards of slash pine (Pinus elliottii L.) in the coastal region of southeastern USA, particularly Florida (Ebel et al. 1980). With multiple generations per year, infestations of D. ebeli can be severe, especially in seed orchards infected by the southern pine cone rust, Cronartium strobilinum Hedgc. & Hahn (Merkel 1958, J. Forestry 56:651 ).

PATHOGENIC MICROORGANISMS ASSOCIATED WITH THE SOUTHERN PINE CONEWORM (LEPIDOPTERA: PYRALIDAE) ATTACKING LOBLOLLY PINE

Abstract Larvae of the Southern pine coneworm, Dioryctria amatella (Hulst) (Lepidoptera: Pyralidae), were collected monthly during the growing seasons of 1996 and 1997 from loblolly pine, Pinus taeda L., seed orchards in Alabama, Florida, Georgia, South Carolina, and Virginia, and examined for pathogenic microorganisms. One fungus, Beauveria bassiana (Bals.) Vuill, a granulosis virus (Baculoviridae: Eubaculovirinae), and a protozoan (phylum Microspora) were found. Five larvae from three localities were infected with B. bassiana, 37 larvae from six localities were infected with the granulosis virus, and 69 larvae from 5 locations were infected with the microsporidian. Laboratory trials confirmed that B. bassiana and the granulosis virus caused coneworm mortality. B. bassiana isolates from all three locations were equally virulent to late instar larvae. Spores of the unidentified microsporidian are free, elongate oval, binucleate and contain 13-14 turns of an isofilar polar filament. The primary sites of infection were the Malpighian tubules and the silk glands. The microsporidian was found in 2 to 51% of larvae sampled. It caused 100% mortality in early instar larvae allowed to feed on artificial diet contaminated with 3 × 103 or 4.5 × 103 spores. More work is needed to determine the importance of these pathogens in regulating populations of southern pine coneworms or their potential utility in an IPM program.

Parasitoid complex of the mealybug Oracella acuta (Lobdell) (Hemiptera: Pseudococcidae), in Georgia, USA

The parasitoid complex of the mealybug Oracella acuta (Lobdell) was examined in two field populations in Georgia in 1995–96. Allotropa n. sp. and Zarhopalus debarri Sun were the primary endoparasit...