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.

Several chemical insecticides and the entomopathogenic nematode, Steinernema carpocapsae (Weiser) (All strain), were evaluated for efficacy against the West Indian sugarcane weevil, Metamasius hemipterus sericeus (Olivier), in laboratory and field tests. Three different bioassays and a field study with sugarcane demonstrated that S. carpocapsae were efficacious against larvae but not adults of the weevil. These bioassays also demonstrated that adults of M. h. sericeus were killed by labelled rates of commercial formulations of acephate 75WP, carbofuran 2F, chlorpyrifos 4 EC, cyfluthrin 2 EC, disulfoton 15G, imidacloprid 2F, isofenphos 2I, lindane 25WP, and Vydate L. In a field test with weevil-infested Canary Island date palms, Phoenix canariensis Hortorum ex Chabaud, lindane (25 WP, 1.5 g AI/palm), and imidacloprid (75 WP, 1.2 g AI/palm) had the greatest effect on the percentage mortality of total weevils present per palm (> 60%) followed by S. carpocapsae (8 × 10⁶ infective juveniles [IJs]/palm) (51%) and acephate (2.9 g AI/palm) (39%) which were statistically equal to the controls (14%). Control palms harbored over 200 M. h. sericeus per tree in the petioles and stem periphery. Because of the potential for high weevil production per palm and the cryptic habitat of the boring stages of this weevil, chemical insecticides and/or entomopathogenic nematodes will need to be applied frequently and over a long period of time for effective management.

The majority of the literature concerning fungus gnats in the genus Bradysia (Family Sciaridae) can be divided into two groups, addressing their cytogenetics or their role as economically important pests. Cytological anomalies in sciarids are recognized in (1) chromosome complement, (2) differential chromosome contributions of the sperm and egg, (3) alteration of chromosome complement during embryogenesis, (4) and alteration during gametogenesis. The literature concerning these cytological events is reviewed within the context of the development of the science of cytogenetics and as they relate to the taxonomy and systematics of this group. Although species of Bradysia were recognized as pests of various seedling plants over a century ago, their economic importance in plant and mushroom production was largely overlooked until recently. A review of the scientific literature on the biology and management of the sciarids indicates that members of the genus Bradysia may be especially pestiferous in greenhouse plant production. Although, a fungal food source appears to be critical to successful development and reproduction of fungus gnats, larvae also will feed on healthy plant tissue. Feeding activities of larvae directly damage seedlings, whereas both larvae and adults indirectly contribute to plant damage through the spread of fungal phytopathogens. The relatively recent confirmation of fungus gnats as potential disseminators of plant pathogens has placed these insects in the category of a more serious pest. As expected with any recently recognized pest, critical information regarding monitoring and economic thresholds is lacking. However, because these flies have been considered a nuisance, chemical control methods are available, as are alternatives which have been integrated most successfully into management programs in European glasshouses.

Field studies were conducted in Virginia cornfields in 1990 and 1991 to evaluate the effect of trap size on numbers of Diabrotica virgifera virgifera LeConte adults caught on unbaited Pherocon AM and Olson yellow sticky traps. No significant differences in trapping efficiency (i.e., catch per unit area) were detected on Pherocon AM traps whose sizes had been reduced by either 50% or 75% when compared with standard Pherocon AM no-bait traps. Likewise, no significant difference in trapping efficiency was detected between Olson traps whose sizes had been reduced 50% and full-size Olson traps (212.9 cm²). However, significantly more western corn rootworm adults per unit area were caught on Olson yellow sticky traps compared to Pherocon AM traps whose sizes had been reduced 50%. Comparative costs and precision values for reduced-size Pherocon AM and Olson yellow sticky traps are discussed.

Condensed tannin is generally considered an example of a quantitative plant allelochemical defense, and catalpol an example of a qualitative chemical defense. The effects of these compounds on the growth and survival of a tachinid parasitoid, Compsilura concinnata (Meigen), reared in the gypsy moth, Lymantria dispar (L.), were compared. Each chemical was incorporated into synthetic diets in a range of ecologically relevant doses and fed to host larvae. Larvae were fed in each of two ways: immediately after parasitization (one day after fourth instar molt), and from egg hatch onward. Growth and survival of unparasitized gypsy moth larvae on test diets were also monitored. No significant effect of either catalpol or condensed tannin on C. concinnata growth or puparial survival was observed. Tannin did lengthen development time of unparasitized host larvae from fourth stadium onward, and lowered pupal weights of larvae fed tannin from egg hatch onward. Catalpol had no significant impact on overall gypsy moth larval development, indicating that this insect is able to compensate for the reduction in weight gain reported to be caused by catalpol in younger larvae. Mortality in all experiments was insignificant. It appears that these phytochemicals are more similar in their effects on the parasitoid than was predicted based on their roles as toxins and digestibility-reducers in herbivores. The data also suggest that generalist tachinid parasitoids such as C. concinnata may be more tolerant of allelochemicals in their host's diet, than their hymenopteran counterparts.

Larval feeding by Phyllophaga crinita (Burmeister) and Anomala spp. (mixed populations of A. flavipennis Burmeister and A. foraminosa Bates) was studied under simulated field conditions in northern Tamaulipas, Mexico. Each month from July 1994 to February 1995, 50 field-collected larvae of P. crinita and Anomala spp. were placed individually in plastic pots with soil and corn seeds, and damage was evaluated 10 d after seedling emergence. Secondinstar P. crinita caused 41% root loss in July, whereas third instars caused most damage (66–88% root loss) during July–September. Feeding by P. crinita decreased gradually from October to December, and ceased in January–February. In contrast, feeding by Anomala spp. peaked in July and again in November (73 and 53% root loss, respectively), a result of the bivoltine life cycle of these species in this region. The relationship of these findings to similar studies is discussed.

Bioassays were conducted to determine the susceptibility of five lepidopteran defoliators to a nuclear polyhedrosis virus (NPV) isolated from the celery looper, Anagrapha falcifera (Kirby). Tobacco budworm, Heliothis virescens (F.), exhibited the greatest susceptibility, LC₅₀ = 2,328PIB/ml, and velvetbean caterpillar, Anticarsia gemmatalis (Hübner), exhibited the least susceptibility, LC₅₀ = 5,176,038 PIB/ml, after 7 d of feeding at the 5 × 10⁴ PIB/ml dosage. Corn earworm, Helicoverpa zea (Boddie), soybean looper, Pseudoplusia includens (Walker), and beet armyworm, Spodoptera exigua (Hübner), expressed intermediate levels of susceptibility, LC₅₀ - 11,742, 14,195, 14,614 respectively, after 7 d of feeding at the 5 × 10⁴ PIB/ml dosage. These results were consistent at days 10 and 14 indicating the relative activity of the virus against each species.

The relative toxicities (comparing LD₅₀ and LT₅₀s) of two synthetic pyrethroids (cypermethrin and fenvalerate), two organophosphorus insecticides (chlorpyrifos, diazinon), three carbamates (propoxur, carbaryl, bendiocarb), a phenylpyrazole representative (fipronil), and a heterocyclic nitromethylene representative (imidacloprid or NTN 33893) were assessed with topical bioassays in the laboratory against the convergent lady beetle, Hippodamia convergens Guérin Méneville. LD₅₀ values decreased (i.e., toxicity increased) with an increased time after application of a specific insecticide. The differences between the LD₅₀ values caused by various insecticides were significant. Among tested insecticides, cypermethrin and bendiocarb were the most toxic; fipronil was the least toxic. H. convergens responded differently to different insecticides within the same class. Beetles exhibited similar responses to both organophosphorothionates chlorpyrifos and diazinon 24 to 72 h after application. Of the carbamates, propoxur was 2.4 and 3.5 times less toxic than carbaryl and bendiocarb, respectively. Of the pyrethroids tested, cypermethrin was significantly more toxic than fenvalerate. At 800 ppm, cypermethrin and bendiocarb were the fastest in killing H. convergens among the tested insecticides. The ranking of insecticides in decreasing order of LT₅₀ values was as follows: fipronil > diazinon > chlorpyrifos > propoxur > carbaryl > fenvalerate and imidacloprid.

Field observations of virgin female grape root borers (Vitacea polistiformis Harris) were made throughout daylight periods under different pheromone treatments and doses. The pheromone compounds used were: the grape root borer pheromone, a 99:1 blend of E,Z-2,13-octadecadien-l-ol acetate (EZ) and Z,Z-3,13-octadecadien-l-ol acetate (ZZ); EZ alone; and ZZ alone. Two different pheromone dispensers were used – rubber septa and Shin-Etzu twist-tie ropes. Treatments with 99:1 EZ: ZZ and 100% ZZ significantly reduced the ability of females to attract a mate. Shin-Etzu ropes were the most effective dispenser for prevention of mating.

Eight Nicotiana species and three species accessions were grown and their sugar esters were isolated. Nicotiana trigonophylla, N. palmeri, and N. glutinosa gave the highest sugar ester yields. Sugar ester isolates were bioassayed at concentrations from 1.0 to 0.05 mg/ml against nymphs of Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae). The highest mortalities were observed with isolates from N. gossei and N. langsdorffii. As the sugar ester isolate from N. gossei contained both sucrose esters and glucose esters, these were bioassayed separately and both caused high mortality. The isolates of three N. glutinosa accessions varied in sucrose ester and labdane terpenoid content; labdane fractions were less toxic than sucrose ester fractions. Nicotiana glutinosa 24, N. langsdorffii, and N. trigonophylla, in addition to N. gossei, showed good potential as sources of biorational insecticide against whitefly.

Twelve independently transformed lines of transgenic corn (Zea mays L.) expressing the CryIA(b) insecticidal protein from Bacillus thuringiensis var. kurstaki were field tested to evaluate their resistance to the corn earworm, Helicoverpa zea (Boddie). Silks of the primary (=top) ears of transgenic [CryIA(b) positive] and isoline control plants [no CryIA(b) protein] were artificially infested with first-instar H. zea larvae and the length of ear penetration was measured after 19 d. Eight of the 12 lines had significantly less ear damage than their respective isoline controls; 3 transgenic lines reduced H. zea feeding damage by > 75% and stunted surviving H. zea larvae. Concentration of the CryIA(b) protein (μg/g fresh weight) in silks of the transgenic lines, determined using ELISA, ranged from 0.0 to 1.28 μg/g. Within transgenic lines, there was a weak (P < 0.06) negative relationship between the concentration of CryIA(b) protein in fresh silks and the length of H. zea ear penetration.

Samples collected from 1989 to 1992 document that the diamondback moth, Plutella xylostella (L.) was introduced into New York in early spring on cabbage, Brassica oleracea capitata (L.), transplants grown in the southern United States. During 1989, transplant shipments from five transplant companies in Florida, Georgia and Maryland were sampled for P. xylostella. In 1989, average seasonal infestations per transplant company ranged from 1.3 to 3.5 P. xylostella per 100 transplants. During June, when the majority of transplants arrived in New York, P. xylostella infestations were as high as 12.8 insects per 100 transplants on an individual shipment. Infestations by cabbage looper, Trichoplusia ni (Hübner), imported cabbageworm, Artogeia (=Pieris) rapae (L.), and cabbage webworm, Hellula rogatalis (Hulst), on an individual shipment were as high as 19.7 insects per 100 transplants. Compared with a standard susceptible field population, the P. xylostella which were collected from transplants demonstrated moderate to high (> than 100-fold in one case) levels of resistance to permethrin or methomyl. In 1990, average seasonal infestations per transplant company varied from 0.3 to 12.0 P. xylostella per 100 plants, but an individual shipment from Florida had 30.4 P. xylostella per 100 transplants. A population of P. xylostella collected in 1990 from Florida transplants had >200-fold resistance to methomyl. Despite intensive treatments, a New York grower who used the transplants with high contamination of resistant P. xylostella was unable to achieve acceptable control in his field. Samples collected from 1989 to 1992 from a transplant grower in Maryland indicate that better management in the field can reduce contamination levels to < 0.5%. The introduction of P. xylostella, especially those resistant to insecticides, on transplants poses a serious threat to cabbage growers and interregional management strategies should be adopted.

The beet armyworm, Spodoptera exigua (Hübner), is an important pest which is difficult to control because it is resistant to nearly all registered insecticides. A new commercial formulation of a nuclear polyhedrosis virus that is pathogenic to beet armyworm larvae, SPOD-X^®, was tested with and without a fluorescent brightener, Tinopal LPW. The effects on larvae from six colonies of the beet armyworm which had recently been established from field collections in Georgia, Alabama and Mississippi were compared with a laboratory colony which had been maintained in the laboratory for 2 years. The LC₅₀ was lower in all bioassays with SPOD-X in 0.25% Tinopal LPW than with SPOD-X in water, although in 3 of 12 bioassays the difference was not significant based on overlapping 95% confidence intervals. The mean LC₅₀ for SPOD-X in water was 376 polyhedral occlusion bodies per cup (surface area 800 mm²). The mean LC₅₀ for SPOD-X in 0.25% Tinopal LPW was 30 polyhedral occlusion bodies per cup. The LC₅₀ for SPOD-X in water was not significantly different between the laboratory colony and 5 of 6 field-collected colonies when bioassayed concurrently. There was no significant difference in LC₅₀ for SPOD-X in 0.25% Tinopal LPW between the laboratory colony and any of the field-collected colonies. Thus, Tinopal LPW enhanced the infectivity of SPOD-X for beet armyworm larvae in laboratory tests and reduced the variability of response of the beet armyworm colonies to the virus.