In northeastern Mexico the Mexican fruit fly, Anastrepha ludens (Loew), breeds on its native host, yellow chapote, Casimiroa greggii (Wats.), which typically produces fruit in the spring. Peak populations of the fly occur in late spring or early summer when adults emerge from the generation of larvae which developed in the spring crop. The parents of the spring generation are flies attracted into the groves of yellow chapote by the presence of fruit. Thus, the reproductive phenology of the fly population depends on the reproductive phenology of the host plant. The reproductive phenology of the host plant follows ambient conditions, in particular, the timing and quantity of rainfall during the preflowering and fruiting season. A prolonged fruiting period can result in production of 2 successive generations of the fruit fly. Infestation rate of the fruit is inversely proportional to the size of the crop; a predictable outcome of the synchronized mass fruiting paradigm (environmental saturation) as a strategy to escape or limit depredation. A strategy to protect a fruit crop might be more effective by targeting the early ovipositing females rather than the succeeding larger peaks of adults.

Silicate slag was applied to soil of Captiva, Floratam, and Raleigh varieties of St. Augustinegrass to measure the effect of plant silicon on resistance of the varieties to southern chinch bugs, Blissus insularis Barber, and plant disease. In general, silicate slag addition increased Si and Cu content in leaves but tended to decrease P and Mg concentrations. Tissue nutrient contents were generally lowest for Floratam; this trend occurred both with and without silicate slag amendment, indicating a lower nutrient requirement than with other varieties. Chinch bug survival was lowest and development slowest on Captiva which was the only variety with resistance to the insects. There were no significant differences in survival or developmental rates of chinch bugs between silicon treatments within any of the 3 varieties. In disease assessments, Raleigh was more susceptible to gray leaf spot than Captiva or Floratam. However, the addition of Si resulted in significant disease reduction in Raleigh. The addition of Si resulted in disease reduction in Floratam as measured by disease incidence, but not severity. The addition of Si slag caused significant increases in stolon number, stolon length, and leaf blade width in 1 - 2 varieties. Varieties varied in response to Si fertilization among 6 growth characters measured.

The pecan weevil, Curculio caryae (Horn), is a key pest of pecan in North America. Entomopathogenic nematodes have potential as alternative control agents for C. caryae. In prior studies, when single applications of entomopathogenic nematodes were applied during adult weevil emergence, only moderate efficacy was observed. The objective of this study was to determine the compounded impact of multistage nematode applications on C. caryae mortality over a 2-year period. Experiments were conducted in a pecan orchard in Byron, GA. In the fall of 2007, freshly-emerged C. caryae larvae were placed in pots under the tree canopy. The nematode, Steinernema carpocapsae (Weiser), was applied 3 times in spring through fall of 2008 (targeting C. caryae larvae) and 3 times during the spring and summer of 2009 (primarily targeting adults). The percentage of surviving C. caryae was determined in the fall of 2008 and 2009, approximately 1 and 2 years after larvae emerged. In 2008 (1 year postemergence), the number of surviving C. caryae was significantly less in treated pots (3.75%) compared with untreated pots (7.38%). In 2009 (2 years postemergence), the number of surviving C. caryae was reduced further and was significantly less in treated pots (0.5%) compared with untreated pots (2.63%). When corrected for natural mortality, after 2 years the nematode treatments provided 81% control. These results indicate promise for reducing the weevil below economic levels through repeated multistage applications of S. carpocapsae. In future research, the approach will be tested on an orchard scale, and nematode application rates and timing will be optimized.

Barley yellow dwarf virus (BYDV) and Cereal yellow dwarf virus (CYDV) are two important aphid-vectored viruses of small grains worldwide. In the Southeastern U.S., there is an absence of wheat, oat and barley during summer months. Thus, the availability of alternative summer hosts for the viruses and their vectors in the field is potentially critical for yellow dwarf epidemiology in the southeast. A 2-year survey of bahiagrass (Paspalum notatum Flugge), limpograss [Hemarthria altissima (Poir) Stapf & Hubb.], and eastern gamagrass (Tripsacum dactyloides L.) populations from the North Florida Research and Education Center, Marianna, FL. showed that bahiagrass and limpograss can act as alternative summer hosts of BYDV-PAV and CYDV-RPV. Additionally, bahiagrass also was shown to harbor BYDV-MAV. The finding of BYDV and CYDV on bahiagrass and limpograss indicates the potential of these perennial pasture grasses to act as “green bridges” between small grain seasons for yellow dwarf viruses. For bahiagrass and limpograss to act as sources of inoculum in yellow dwarf epidemiology, one or more aphid species will have to transmit the virus from these grasses to commercial small grains. However, very few aphids were collected and no known B/CYDV vector was found on these grasses in the 2 years of sampling. Sipha flava (Forbes), an aphid not listed as B/CYDV vector, was the only species collected on bahiagrass. Additionally, in B/CYDV transmission studies reported here, winged R. padi did not survive on bahiagrass and failed to transmit B/CYDV from bahiagrass to oats or from oats to bahiagrass.

Several native Lygus spp. (Hemiptera: Miridae) feed on buds, flowers and immature seeds of canola. These plant resources are also exploited by a recent alien pest now established in southern Alberta, Canada: the cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham) (Coleoptera: Curculionidae). A caged study was conducted with Brassica napus L. in 2000 and 2002 to determine if various combinations and densities of lygus and seedpod weevils (0, 10 10, 20 of either, 20 20, 40 40, individuals per cage) affected yield and its components such as number of branches, pods and seed weight. Under severely dry conditions, cages with the intermediate (20 20) and high (40 40) insect combinations had lower grain yield as well as number of racemes and pods per raceme relative to control cages with no insects added. Under more humid conditions in 2002, similar results were observed but the damage by the cabbage seedpod weevil at 20 adults per cage was more apparent than in 2000. These results suggest that in most years the weevil is a more serious pest than lygus bugs but low combined densities do not decrease yield. Furthermore, in southern Alberta at low or moderate densities, these late-season pests do not appear to stimulate plants to overcompensate. There was no indication of competition between these two insects.

Combinations of commercial fly baits, traps, and cords were evaluated for integration into a fly management system. Imidacloprid granular and sprayable baits caused house fly, Musca domestica L., mortality at a faster rate than methomyl granular fly bait; however, the methomyl granular bait had the highest overall mortality at 24 h. Commercial fly traps had a variety of designs that resulted in differences in efficiency for retaining house flies. Among 6 commercial traps tested, the Trap n' Toss™ (Farnam Companies, Inc., Phoenix, AZ) captured the most flies, and the design was selected for our field cage studies. These cage studies with flies (~300) determined that without treated cord or attractant, fly traps captured and killed 5% of the fly population; whereas, fly traps with attractant captured and killed only 14% of the population in the first 24 h. A 46-cm cord (6 mm diam.) dipped in 2.5% imidacloprid was looped around a fly trap (identical to the Trap n' Toss), and the trap was baited with commercial fly attractant. The addition of the bait-treated cord killed 60 - 70% of flies at 24 h and 84 - 90% at 48 h. However, bait-treated fly cords used alone killed 70% of flies at 24 h and 94% at 48 h and demonstrated the relatively poor efficiency of commercial fly traps. Fly annoyance was eliminated by the high fly mortality resulting from the use of bait-treated cords. Bait-treated cords can be used to improve the efficiency of fly management programs, either in conjunction with commercial fly traps or alone.

Thrips-transmitted Tomato spotted wilt (TSW) virus (Family Bunyaviridae Genus Tospovirus) is an important problem in tomato in the southeastern United States. Tobacco thrips, Frankliniella fusca (Hinds), and western flower thrips, Frankliniella occidentalis (Pergande), (Thysanoptera:Thripidae) are the known major vectors of TSW virus in Georgia; however, the temporal relationship of thrips to TSW disease incidence in tomato is not clear. Field studies were conducted in 2005 and 2006 specifically to compare thrips population dynamics to disease incidence in untreated tomato fields. Populations of F. fusca were observed to increase approximately 3 wks prior to increased TSW incidence and correlated positively with TSW when considering this delay. Populations of F. occidentalis positively correlated with TSW occurrence in 2005, but not in 2006. Additionally, tomato fruit yield decreased greater in plants with early TSW symptoms than in plants that developed symptoms later in the season. Both results suggest early-season thrips management targeted at F. fusca during the early-growth stages of tomato could help to reduce the risk of yield loss in tomato due to this disease.

Captures of the invasive brown marmorated stink bug, Halyomorpha halys (Stål), were significantly greater in pyramid traps baited with the known attractant, methyl (2E,4E,6Z)- decatrienoate, compared with unbaited traps. A dose-dependent response by adults to lures formulated with increasing amounts of methyl (2E,4E,6Z)-decatrienoate and deployed in association with black pyramid traps also was observed. Among pyramid traps representing different visual stimuli including black, green, yellow, clear, white and yellow, significantly greater captures were recorded in baited black pyramid traps for adults in 2009 and nymphs in 2010 compared with other trap types; the dark upright silhouette created by this trap likely represents a trunk-mimicking visual stimulus to foraging bugs. A ground-deployed baited black pyramid trap also captured significantly greater numbers of nymphs and adults compared with canopy-deployed commercially available baited traps from Japan. Based on semi-field cage studies, brown marmorated stink bug was confirmed to be bivoltine within the mid-Atlantic region. Thus, the need for a reliable monitoring tool to detect presence, abundance and seasonal activity of brown marmorated stink bug in tree fruit and other cropping systems is critical.