R. Chris Williamson

Trapping Phyllophaga spp. (Coleoptera: Scarabaeidae: Melolonthinae) in the United States and Canada using sex attractants.

Abstract The sex pheromone of the scarab beetle, Phyllophaga anxia, is a blend of the methyl esters of two amino acids, L-valine and L-isoleucine. A field trapping study was conducted, deploying different blends of the two compounds at 59 locations in the United States and Canada. More than 57,000 males of 61 Phyllophaga species (Coleoptera: Scarabaeidae: Melolonthinae) were captured and identified. Three major findings included: (1) widespread use of the two compounds [of the 147Phyllophaga (sensu stricto) species found in the United States and Canada, males of nearly 40% were captured]; (2) in most species intraspecific male response to the pheromone blends was stable between years and over geography; and (3) an unusual pheromone polymorphism was described from P. anxia. Populations at some locations were captured with L-valine methyl ester alone, whereas populations at other locations were captured with L-isoleucine methyl ester alone. At additional locations, the L-valine methyl ester-responding populations and the L-isoleucine methyl ester-responding populations were both present, producing a bimodal capture curve. In southeastern Massachusetts and in Rhode Island, in the United States, P. anxia males were captured with blends of L-valine methyl ester and L-isoleucine methyl ester. Resumen La feromona sexual del escarabajo, Phyllophaga anxia, es una mezcla de los ésteres metílicos de dos aminoácidos, L-valina y L-isoleucina. Se condujo un estudio de campo usando diferentes mezclas de los dos componentes en 59 sitios de Estados Unidos y Canada. Más de 57,000 machos de 61 especies dePhyllophaga fueron capturados e identificados. Tres de los resultados más importantes incluyen: (1) el extenso uso de los dos componentes [de las 147 especies de Phyllophaga (sensu stricto), en Estados Unidos y Canada, fueron capturados machos de cerca del 40% de ellas.]; (2) para la mayoría de las especies, la respuesta intraespecífica de los machos a las combinaciones de los dos aminoácidos fue consistente entre años diferentes, y en todos los sitios geográficos; y (3) un inusual polymorfismo de la feromona fue descrito para P. anxia. Poblaciones de algunos sitios fueron atrapados sólo con valina, mientras que poblaciones de otros sitios fueron atrapados sólo con isoleucina. También se encontraron sitios donde las poblaciones responden a ambos componentes, valina e isoleucina, produciendo una curva de captura bimodal. En el sureste del estado de Massachusetts y en Rhode Island, en Estados Unidos, machos de P. anxia fueron atrapados en trampas con mezclas de valina e isoleucina.

Leaf biomechanical properties as mechanisms of resistance to black cutworm (Agrotis ipsilon) among Poa species

Biomechanical properties can be important parameters in resistance of plants to herbivorous insects. As plants age, however, there can be dramatic changes in physical defenses that can then influence their susceptibility to insect herbivores. We measured changes in leaf biomechanical properties during ontogeny of Poa species and the relationship of these changes to the development of a generalist herbivore, the black cutworm, Agrotis ipsilon Hufnagel (Lepidoptera: Noctuidae), was investigated. Larvae were reared on two representative age classes, i.e., young (<60 days after planting) and old (>1 year after planting), of foliage in laboratory assays. Foliage generally reaches a peak fracture force between 80 and 109 days after planting depending on grass type. Foliage from old plants was significantly tougher than that of young plants, and black cutworm larvae reared on foliage from young plants gained significantly (ca. four times) more weight than those fed on foliage from old Poa plants. In addition, fracture force has a negative relationship with black cutworm development. Plant fiber, particularly neutral detergent fiber accounted for 65 and 46% of the variation in fracture force and larval development, respectively. These results provide additional insight into how plant ontogeny influences physical defenses to an insect herbivore in a grass system. Likewise, this is seemingly the first study to suggest a mechanism for host plant resistance to black cutworm. Plant fiber may be a useful trait to explore in plant improvement programs in which black cutworm is a primary pest (e.g., managed turfgrass).

Multiple Morphological Measurements as Larval Indicators for Saperda vestita (Coleoptera: Cerambycidae)

Abstract Ten sclerotized morphological structures were measured to determine the number of instars of the linden borer, Saperda vestita Say (Coleoptera: Cerambycidae). Linear regression analysis revealed a significant relationship between maximal cranial width and the other structures measured, including length of the terminal labial palpomere, length of the first thoracic spiracle, width of the first thoracic spiracle, length of clypeolabral suture, length of frontoclypeal suture, cranial width measured at antennal insertions (from outside edges), maximal prothoracic width, mesal pronotal length, and length from apical margin of labrum to distal end of the prothorax. Linden borer instar number was determined through the use of frequency distribution diagrams. Mean, standard error of the mean, Dyar’s ratio, and Crosby’s ratio were calculated and evaluated for each instar designation to confirm that none of the five to six instars of S. vestita was overlooked.

Fungicides affect Japanese beetle Popillia japonica (Coleoptera: Scarabaeidae) egg hatch, larval survival and detoxification enzymes

BACKGROUND Larvae of the Japanese beetle, Popillia japonica (Coleoptera: Scarabaeidae), have a patchy distribution in soils, which complicates detection and management of this insect pest. Managed turf systems are frequently under pest pressure from fungal pathogens, necessitating frequent fungicide applications. It is possible that certain turfgrass fungicides may have lethal or sublethal adverse effects on eggs and larvae of P. japonica that inhabit managed turf systems. In this study, eggs and first-, second- and third-instar larvae were treated with the fungicides chlorothalonil and propiconazole, and survival was compared with that of untreated controls as well as positive controls treated with the insecticide trichlorfon. RESULTS Chlorothalonil reduced survival of first-instar larvae treated directly and hatched from treated eggs. Propiconazole delayed egg hatch, reduced the proportion of eggs that successfully hatched and reduced survival of first-instar larvae treated directly and hatched from treated eggs. Sublethal doses of the fungicides lowered the activities of certain detoxification enzymes in third-instar grubs. CONCLUSIONS Fungicide applications to turfgrass that coincide with oviposition and egg hatch of white grubs may have sublethal effects. This work is applicable both to high-maintenance turfgrass such as golf courses, where applications of pesticides are more frequent, and to home lawn services, where mixtures of multiple pesticides are commonly used.

Suitability of Creeping Bentgrass and Bermudagrass Cultivars for Black Cutworms and Fall Armyworms (Lepidoptera: Noctuidae).

ABSTRACT The black cutworm, Agrotis ipsilon Hufnagel, and fall armyworm, Spodoptera frugiperda Smith (Lepidoptera: Noctuidae), are common turfgrass pests of golf courses in the southeastern United States. Heat-tolerant bentgrass (Agrostis stolonifera L.) cultivars are expanding the range of bentgrass further south, but these cultivars have not been studied for their potential host plant resistance to black cutworm or fall armyworm. The goals of the study were to investigate feeding response of black cutworm and fall armyworm to these newer heat-tolerant creeping bentgrass cultivars, as well as commonly used cultivars of bermudagrass [Cynodon dactylon (Loppers.)]. Choice and no-choice feeding assays and fecundity tests were conducted in the laboratory and greenhouse to evaluate performance and preference of the two insects. When given a choice, neither black cutworm nor fall armyworm showed a preference for the majority of new cultivars tested. There were no differences in leaf area consumption or insect development for either pest in no-choice feeding assays. Black cutworm females preferred laying eggs in bentgrass compared with bermudagrass, but will oviposit onto bermudagrass, suggesting that both turf species are suitable hosts of this pest. The broad host ranges of generalist caterpillar pests of turfgrass hinder the application of host plant resistance in integrated pest management on golf courses.

Black Cutworm (Lepidoptera: Noctuidae) Flight Activity on a Golf Course in Central Alabama

Black cutworm, Agrotis ipsilon (Hufnagel), is a major agricultural insect pest that attacks a wide variety of cultivated plants (Crumb 1929). The insect is also a serious pest that feeds on creeping bentgrass, Agrostis palustris Huds., the predominant turfgrass species on golf course putting greens. Feeding damage by black cutworm, especially older larvae (i.e., 4~6th instars) creates sunken pock-marks or suppressions, resulting in the reduction of uniformity and smoothness of putting green surfaces (Vittum et al. 1999). Although there was no significant relationship between black cutworm adult population and larval infestation on golf course putting greens (Hong & Williamson 2004), monitoring adult population can provide some insight on potential larval activities on putting greens (Potter 1998). Black cutworm is a migratory species (Showers 1997). In Wisconsin, moths are active in May through late Aug or early Sep (Hong & Williamson 2004), which is similar to the flight pattern observed in other northern areas (Levine et al. 1982). However, there is no flight activity during the winter in the northern United States. This is not surprising because generally black cutworm cannot overwinter north of Tennessee (Showers 1997). Of the few black cutworm flight activity studies on golf courses, most focused only on the northern areas. Thus, no references regarding black cutworm flight activity on a golf course are available for the southern United States where these insects overwinter and presumably have a longer flight period. The objective of our study was to investigate black cutworm flight activity on a golf course in the central Alabama. Black cutworm adults were monitored at the Grand National Golf Course, Opelika, Alabama. Two sticky traps (TRECE Inc., Salinas, California) baited with cap-type synthetic sex pheromone (TRECE; BCW 3141-25) were installed in trees at ca. 1.5 m above the turf surface (Hong & Williamson 2004) on 7 Apr 2010. The location of traps was less than 20 m from the creeping bentgrass, a preferred host, on putting greens. The traps and rubber septa containing the synthetic phero-

Evaluation of a Nonconventional Insecticide and Appropriate Application Timing for Destruction of Gypsy Moth (Lepidoptera: Lymantriidae) Egg Masses

Abstract Two field studies were conducted in 2001–2002 and 2003 to evaluate the effectiveness and appropriate application timing of Golden Pest Spray Oil (GPSO) for destruction of gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae), egg masses in Wisconsin. GPSO is a commercially available, registered pesticide that is predominantly comprised of a soybean-oil base (93%); its primary mode of action is by means of suffocation. Because gypsy moth spends the majority (>75%) of its life cycle in the egg stage (August–April), the potential utility of this product by arborists, city foresters, landscapers, and homeowners is high, especially because GPSO is a United States Environmental Protection Agency registered, nonconventional pesticide that is considered relatively nontoxic. When GPSO was applied at a 1:1 ratio with water, >96% control of gypsy moth egg masses was achieved, regardless of application timing (October, 3 d before egg hatch).