John J. Riggins

SUPERCOOLING IN THE REDBAY AMBROSIA BEETLE (COLEOPTERA: CURCULIONIDAE)

Abstract The redbay ambrosia beetle, Xyleborus glabratus Eichoff, (Coleoptera: Curculionidae: Scolytinae) is a severe pest of North American trees and shrubs in the family Lauraceae. Supercooling point (SCP) is an important physiological baseline for cold tolerance studies and could provide useful insights into the invasive potential of X. glabratus in northern latitudes of North America. The supercooling point (SCP) of X. glabratus was experimentally determined on field-collected and artificially cold hardened specimens. Field-collected beetles were captured in Jackson County, Mississippi using Lindgren funnel traps baited with manuka oil lures. Testing was conducted from June through August 2011. The mean SCP for field-collected X. glabratus was -21.7 ± 0.5 °C (± SE). A significant negative trend in the SCPs of field-collected beetles occurred over the summer testing period. Xyleborus glabratus specimens were reared from redbay (Persea borbonia (L.) Sprengel bolts in June 2012 and artificially cold hardened in a low temperature incubator at a thermo-photoperiod of 7 °C:2 °C (10:14 h L:D) for 31 days. Artificially cold hardened X. glabratus supercooled to a mean temperature of -23.9 ± 0.4 °C (± SE), which was significantly lower than that of field-collected beetles. Biometric indices of beetles (size, weight, and size x weight interaction) had no effect on the mean supercooling SCPs of either field-collected or artificially cold hardened beetles. Results from environmentally conditioned beetles suggest that X. glabratus has a high degree of thermal plasticity. Based on the artificially cold hardened mean SCP, X. glabratus and laurel wilt disease have the possibility to impact sassafras and northern spicebush throughout eastern North America. The data, although preliminary, suggests that a previous spatio-temporal model based on climate match data may have substantially underestimated the geographical area that may be affected by X. glabratus. This study will help form the basis of building and validating models to better predict the North American invasion potential of X. glabratus.

Feeding Preference of Native Subterranean Termites (Isoptera: Rhinotermitidae: Reticulitermes) for Wood Containing Bark Beetle Pheromones and Blue-Stain Fungi

Surprisingly little research has been conducted to investigate interactions between subterranean termites and bark beetles. Facilitative interactions between these organisms could easily alter stand dynamics and impact wood utilization strategies. A series of American Wood Protection Association Standard E1-09 “choice tests” were carried out to determine the feeding preference of Reticulitermes flavipes Kollar (Isoptera: Rhinotermitidae) for blue-stained sapwood and sapwood impregnated with various bark beetle pheromones. Reticulitermes flavipes exhibited a feeding preference for both air-dried and kiln-dried blue-stained sapwood, unstained sapwood treated with frontalin, and air-dried blue-stained sapwood treated with a 0.02% solution of both frontalin and endo-brevicomin. The implications of these results are far reaching, with particular relevance to forest health, ecology, and utilization.

Preference of Formosan Subterranean Termites for Blue-Stained Southern Yellow Pine Sapwood

ABSTRACT Little research has been conducted to investigate interactions between the invasive Formosan subterranean termite, Coptotermes formosanus Shiraki, and pine bark beetles native to the southeastern United States. Facilitative interactions between these organisms could alter stand dynamics and impact wood utilization strategies. American Wood Protection Association Standard El-09 choice tests were carried out to determine the feeding preference of Formosan subterranean termites for blue-stained versus unstained southern yellow pine sapwood. Three separate colonies of Formosan subterranean termites consumed on average twice as much air-dried blue-stained southern yellow pine sapwood over unstained air-dried controls. Additionally, Formosan subterranean termites consumed over five-times more kiln-dried blue-stained sapwood than unstained kiln-dried control wafers. The implications of these results are particularly relevant to pine forest ecology, nutrient cycling, and the utilization of blue-stained southern pine building products in the southeastern United States, where Formosan subterranean termites have become established.

Effects of Forest Type and Management on Native Wood Wasp Abundance (Hymenoptera: Siricidae) in Mississippi, United States

ABSTRACT The United States has a rich fauna of native Siricidae (wood wasps), but they are rarely studied because they have limited economic impact. In 2004, a non-native wood-boring pest, Sirex noctilio F., was found established in North America. Because S. noctilio is an economically important pest in pine plantations throughout the Southern Hemisphere, interest in the ecology of American native wood wasp populations has increased. A study was conducted during fall 2011 to investigate the effects of forest stand type and characteristics on native wood wasp abundance, and to describe their flight phenology in northeastern Mississippi. In total, 609 native wood wasps were captured, consisting of 608 Sirex nigricornis F. and one Urocerus cressoni Norton. There were significant treatment and location effects that influenced wood wasp abundance. The flight period of wood wasps captured in our study (October–December) was similar to studies in the southeastern United States, but differed from results in Minnesota and the northeastern United States (June–October).Woodwasp abundance was significantly correlated with higher basal area, smaller tree diameter at breast height, and shorter trees, all indicators of forest stand stress. It appears proper silvicultural management of pine plantations may reduce native wood wasp population abundance in the southeastern United States, as it does to S. noctilio in the Southern Hemisphere. We propose implementing management models used for the southern pine beetle to reduce stand hazard of future infestations of native and invasive wood wasps.

Rise and Fall of Red Oak Borer (Coleoptera: Cerambycidae) in the Ozark Mountains of Arkansas, USA

ABSTRACT Oak-hickory forests of the Arkansas Ozarks recently incurred extensive tree mortality due in part to a native wood-boring beetle, the red oak borer Enaphalodes rufulus (Haldeman) (Coleoptera: Cerambycidae). Historically, red oak borer has existed throughout southeastern U.S. forests at relatively low population levels, but Arkansas infestation estimates in 2001 and 2003 reported much higher populations. Red oak borer has a two-year generation with adult emergence occurring synchronously only in odd numbered years. We report here results of whole-tree estimates of pre-emergent red oak borer population numbers from 7 stands in 2005 and 3 stands in 2003 and 2007 in the Ozark National Forest. Trees were felled at each sampling site, cut into 0.5 m sections, split on site with hydraulic log splitters, and a count of live red oak borers was recorded for each tree. In 2001 and 2003, red oak borer population estimates indicated emerging populations much higher than any previously reported. An exponential decrease during a single cohort between 2003 and 2005, and even lower populations in 2007 suggest that red oak borer populations have returned to historic densities. RESUMEN Los bosques de roble-nogal de las montañas Ozark del estado de Arkansas recientemente sufrió una mortalidad de árboles extensiva debido en parte a un escarabajo nativo barrenador de madera, el barrenador de roble rojo Enaphalodes rufulus (Haldeman) (Coleoptera: Cerambycidae). Históricamente, el barrenador de roble rojo ha existido por todos los bosques del sureste de los Estados Unidos con niveles de población relativamente bajos, pero los informes del nivel de infestación en Arkansas en el 2001 y 2003 indica una población mucho más alta. El barrenador de roble rojo cumple una generación en dos años con la emergencia de los adultos, ocurriendo sincrónicamente durante los años de número impar. Reportamos los resultados de los números aproximados de la población pre-emergente del barrenador de roble rojo de los árboles totales de 7 grupos de árboles en 2005 y 3 grupos de árboles en 2003 y 2007 del Bosque Nacional de Ozark. Los árboles en cada uno de los sitios de muestreo fueron tumbados, cortados en secciones del tamaño 0.5 m, partidos con un rajador hidráulico de troncos y se noto el numero de barrenadores de roble rojo vivos encontrados por cada árbol. En el 2001 y 2003, los aproximados de la población del barrenador de roble rojo indicaron la emergencia de poblaciones mucho mas altas que las reportadas anteriormente. Una disminución exponencial durante un solo cohorte entre el 2003 y 2005, y aun poblaciones mas bajas en el 2007 sugerieron que la población del barrenador de roble rojo ha vuelto a las densidades históricas.

Correlation between infection by ophiostomatoid fungi and the presence of subterranean termites in loblolly pine (Pinus taeda L.) roots

Observations of subterranean termites feeding in pine sapwood containing ophiostomatoid fungi prompted the present study aiming to investigate the effect of infection by Leptographium fungi on the probability of encountering subterranean termites in loblolly pine (Pinus taeda L.) roots. Root samples were collected from 2350 loblolly pine trees in Alabama, Texas, Louisiana and Mississippi using hand tools. The presence or absence of subterranean termites in the roots was recorded. Samples were plated on malt extract agar and cycloheximide‐streptomycin malt agar and incubated to determine which, if any, fungal species were present. The presence of Leptographium procerum, Leptographium terebrantis or both was significantly associated with an increased presence of subterranean termites in loblolly pine roots. The results obtained in the present study indicate that complex ecological interactions may exist between ophiostomatoid fungi, as carried by root‐feeding bark beetles, and subterranean termites.

Geographical Approaches for Integrated Pest Management of Arthropods in Forestry and Row Crops

With the proper technology and access to geographical information, it is more important to spend time developing an excellent classification scheme of a remotely sensed attribute of crop and forest vigor than to spend that time collecting multiple samples of insect counts . The ability to define zones from remote sensing images of crop or forest systems provides a vastly improved capacity to assess the sample variability of insect counts. Perspectives on defining zones from remote sensing information, including an examination of some relationships between these zones and insect sample counts, are discussed.

Emergence of adult female Sirex nigricornis F. and Sirex noctilio F. (Hymenoptera: Siricidae) coincides with a decrease in daily minimum and maximum temperature

The establishment and spread of Sirex noctilio F. (Hymenoptera: Siricidae), in northeastern North America necessitates reliable monitoring methods for this alien woodwasp pest of Pinus. The native congener, Sirex nigricornis F., is common across the eastern U.S.A. and has been studied as a proxy for S. noctilio. Predicting the emergence of S. noctilio is important for guiding monitoring efforts. Degree‐day models have been developed to predict flight phenology of S. noctilio and S. nigricornis across eastern North America. These model parameters were tested against three years of S. nigricornis collections from two locations in Arkansas. Neither of the proposed models accurately predicted emergence. The emergence of females for both S. noctilio and S. nigricornis was significantly negatively correlated with minimum and maximum temperature, indicating that emergence increases when minimum and maximum temperatures decrease. These results suggest that, as S. noctilio spreads south, where higher mean temperatures are present, it will emerge later in the season as the temperatures decline compared with the current northeastern population. We propose that monitoring for the spread of S. noctilio in the southeastern U.S.A. should begin slightly before daily temperatures are expected to decline (i.e. mid‐September).

First Records of Xyleborus glabratus (Coleoptera: Curculionidae) in Alabama and in Harrison County, Mississippi

family Lauraceae (Fraedrich et al. 2008). Known hosts include, but are not limited to redbay (Per sea borbonia (L.) Spreng.), avocado (Persea ameri cana Mill.), sassafras (Sassafras albidum (Nutt.) Nees), camphor (Cinnamomum camphora (L.) J. Presl), and swampbay (Persea palustris (Raf.) Sarg.) (Fraedrich et al. 2008). While the direct feeding damage caused by X. glabratus may not be significant, the beetle carries various species of fungal symbionts within mycangia at the base of its mandibles. As the female beetle bores into

First Incidence of Sinoxylon Indicum and Sinoxylon Sudanicum (Coleoptera: Bostrichidae) in Mississippi

Auger beetles (Coleoptera: Bostrichidae), also known as false powderpost beetles, are serious pests of trees, forest products, agricultural crops, and stored vegetable products in most regions of the world (Fisher 1950; Lawrence 2010). There are approximately 570 species in 89 genera worldwide (Lawrence 2010), including approximately 73 native species found in North America (Ivie 2002). Most woodboring bostrichids obtain nutrition from starch, enabling many species to utilize almost any dry wood material from an enormous host range (Ivie 2002). The frequency of non-native bostrichid interceptions at ports of entry and storage facilities around the world has increased during the last decade (Teixeira et al. 2002; Ratti 2004; Filho et al. 2006; Aukema et al. 2011; EPPO 2011; Price et al. 2011). Bostrichids, along with many other woodboring insects, are often accidentally introduced inside solid wood packing material in containerized cargo (Haack 2006). The bostrichid genus Sinoxylon Duftschmid contains 52 species, all of which are native to Asia, Africa, and Southern Europe (Borowski & Wegrzynowicz 2007) and are typically not considered primary pests. Sinoxylon species utilize a wide variety of hosts, including numerous trees, shrubs, herbaceous plants, and bamboos (Filho et al. 2006). Sinoxylon damage is typically caused by the boring of adults and larvae in the stems, branches, or twigs of dead, damaged, or stressed hosts (Nair 2007). One species has even been known to damage lead cables (Filho et al. 2006). Species of Sinoxylon are frequently intercepted in the U.S.A., representing 32% of bostrichid interceptions between 1985 and 2000 (Haack 2006; Price et al. 2011). There have been 289 Sinoxylon interceptions in the U.S.A. between 2007 and 2012 (Brian Saunders, USDA-APHIS-PPQ, Cape Canaveral, Florida, personal communication). In the continental U.S.A., there are 2 established non-native species of Sinoxylon. Sinoxylon anale Lesne and S. conigerum Gerstacker are both established in southern Florida (Peck & Thomas 1998). Another species, S. ceratoniae (L.), may be established in California (Ivie 2002). Sinoxylon anale Lesne is the most economically important and most commonly intercepted species of Sinoxylon, typically arriving in solid wood packing materials (Fisher 1950; Argaman 1987; Teixeira et al. 2002; Sittachaya et al. 2009; Beaver et al. 2011). Sinoxylon anale is native to the Indomalaya and Palearctic ecozones, where it attacks more than 70 species of plants. In the United States, Price et al. (2011) reported 2 interceptions of S. anale in Georgia in 2004 and 2010, both arriving from India in solid wood packing materials. Borowski and Wegrzynowicz (2007) list 3 other species, S. japonicum Lesne, S. sexdentatum (Olivier) (as S. muricatum (L.)), and S. ruficorne Fahaeus, as introduced into the United States, but these records are apparently based on the interceptions reported by Fisher (1950) that do not represent established populations. On 29 Aug 2011 in West Point, Mississippi, United States (N 33°36’25” W 88°39’01”), a substantial infestation of larval and adult Sinoxylon indicum Lesne (Fig. 1A) and S. sudanicum Lesne (Fig. 1B) was discovered in wooden crates and pallets that originated from Pakistan. It is not known if the wood used to construct the crates originated in Pakistan, or whether the wood was treated according to IPPC international standards