Kathleen Demchak

Inoculation of Strawberries with AM Fungi Produced On-Farm Increased Yield

ABSTRACT Inoculation of plants with arbuscular mycorrhizal [AM] fungi has the potential to increase or maintain yields and allow for reduced fertilizer and pesticide application, thereby enhancing agricultural sustainability. Strawberry plants (Fragaria x ananassa Duch. cv. Chandler) were inoculated prior to outplanting with a mixed species inoculum of AM fungi. The inoculum was produced on-the-farm in 2003 in a mixture of compost and vermiculite with bahiagrass (Paspalum notatum Flugge) as host plants. Plants were outplanted into raised black plastic beds on 30 June 2004 and harvested 6–25 June 2005. Inoculation with AM fungi increased yield 17% over uninoculated controls, 5.5 vs. 4.7 kg per ten plant sampling unit, respectively. Inoculation had no significant effect on whole season mean fruit weight, indicating an average increase of 3.6 fruit per plant for inoculated plants over uninoculated plants. Utilization of AM fungus inoculum produced on-farm as an amendment to horticultural potting media for the production of seedlings later outplanted has the potential for significant increases in crop yields.

First Report of Zaprionus indianus (Diptera: Drosophilidae) in Commercial Fruits and Vegetables in Pennsylvania

ABSTRACT. Zaprionus indianus (Gupta) (Diptera: Drosophilidae), an invasive vinegar fly, was found for the first time in Adams County, Pennsylvania, in 2011. It was found in a commercial tart cherry orchard using apple cider vinegar (ACV) traps that were monitoring another invasive vinegar fly, the spotted wing drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae). Coincidentally, the first record of D. suzukii found in Pennsylvania was also found in this same cherry orchard only 3 months earlier as part of a spotted wing drosophila survey effort in raspberry, blackberry, grape, and tart cherry in Adams County. These same crops plus blueberry and tomato were monitored again in 2012. In this article, adult Z. indianus captures in ACV traps and other traps deployed in the aforementioned crops during 2012 season are presented and the economic importance of Z. indianus is discussed.

Evaluation of Strawberry Sap Beetle (Coleoptera: Nitidulidae) Use of Habitats Surrounding Strawberry Plantings as Food Resources and Overwintering Sites

Abstract The matrix of strawberry and alternate host crops, wooded areas, and uncultivated sections that comprises a farm landscape provides not only food resources but also habitat in both a spatial and temporal context. Reports of the strawberry sap beetle as a pest in strawberry in the northeastern United States have increased along with a trend to produce a wider diversity of fruit crops on individual farms. The three objectives of this study focused on determining which, if any, habitats outside strawberry plantings are important to consider when developing control strategies for strawberry sap beetles. First, sampling of wooded areas and multiple crops showed that strawberry sap beetles overwinter not only in wooded areas but also in blueberry and raspberry. No overwintering beetles were found in strawberry. Second, up to a 70-fold increase in mean number of strawberry sap beetles in a no-choice food source experiment indicated that considerable reproduction can occur on blueberry, cherry, raspberry, and strawberry. Third, sampling summer-bearing raspberry, peach, blueberry, and cherry in 2004 and 2005 confirmed that beetles were present, often in high densities (0.1–108.5 strawberry sap beetles/m2), in commercial fields with fruit or vegetable material on the ground. In summary, the beetles are able to feed, complete development, and overwinter in habitats other than strawberry. An effective integrated pest management program to control strawberry sap beetles will need to consider the type of habitat surrounding strawberry fields.

Seasonal occurrence of spotted wing drosophila in various small fruits and berries in Pennsylvania and Maryland

Spotted wing drosophila (SWD) (Drosophila suzukii), a major invasive pest of small fruit crops, was first found in Pennsylvania and Maryland during the 2011 crop season, and since then, it has been established throughout the fruit growing regions of both states. A season‐long field study was conducted to find out the seasonal occurrence of SWD in several fruit crops (e.g. blueberry, tart and sweet cherry, floricane‐fruiting summer red raspberry, blackberry, primocane‐fruiting fall raspberries and table grapes) in Pennsylvania and Maryland in 2014. This is the first study determining seasonal occurrence of SWD using a standard commercial lure (Pherocon® SWD Dual‐Lure™)‐baited traps in this region. In both states, SWD adults were not captured prior to the month of July, and populations of SWD were found to build up in fruit crops only from mid‐July onwards. This indicates early season fruit crops or varieties are not at risk from SWD fruit injury in these two states. Such early fruit crops, for instance strawberry, sweet and tart cherry, are generally harvested before SWD populations build up in this region. In this context, implications of SWD population in various small fruit crops grown in this region and the utility of SWD Dual‐Lure ™ in season‐long monitoring of SWD population are discussed.

Evaluation of Cultural Practices for Potential to Control Strawberry Sap Beetle (Coleoptera: Nitidulidae)

Abstract Strawberry sap beetle, Stelidota geminata (Say) (Coleoptera: Nitidulidae), adults and larvae feed on and contaminate marketable strawberry (Fragaria L.) fruit. The beetle is a serious pest in the northeastern United States, with growers in multiple states reporting closing fields for picking prematurely due to fruit damage. Three options were evaluated for potential to reduce strawberry sap beetle populations. First, the influence of plant structure on accessibility of fruit in different strawberry cultivars to strawberry sap beetle was assessed by modifying plant structure and exposing caged plants to strawberry sap beetle adults. Severity of damage to berries staked up off the ground was similar to damage to those fruit contacting the soil, showing that adults will damage fruit held off the ground. Second, baited traps were placed at three distances into strawberry fields to determine whether overwintered beetles enter strawberry fields gradually. Adult beetles were first caught in the strawberries ≈19 d after occurring in traps placed along edges of adjacent wooded areas. The beetles arrived during the same sampling interval in traps at all distances into the fields, indicating that a border spray is unlikely to adequately control strawberry sap beetle. Third, the number of strawberry sap beetle emerging from strawberry for 5 wk after tilling and narrowing of plant rows was compared in plots renovated immediately at the end of harvest and in plots where renovation was delayed by 1 wk. In the 2-yr study, year and not treatment was the primary factor affecting the total number of emerging strawberry sap beetle. Overall, limited potential exists to reduce strawberry sap beetle populations by choosing cultivars with a particular plant structure, applying insecticide as a border spray, or modifying time of field renovation.

Tomato nutrient uptake as affected by limestone type

Abstract Experiments were conducted at the Horticultural Research Farm at Rock Springs, PA and with a commercial grower at Clarks Summit, PA in 1986–8. ‘Count II’ tomato transplants (Lycopersicum esculentum Mill) were grown in rows 1.52 m apart with 30 cm inrow spacing. Seven limestone type treatments were applied at 11.3 t/ha with a check. Calcitic (trace of Mg) and dolomitic (12% Mg) types and 5 mixtures with 2, 4, 6, 8 and 10% Mg were combined with banded NPK fertilizers in 4 replications. Of special interest was the Ca/Mg balance. Leaf Ca was increased by the calcitic but not by the dolomitic type. Leaf Mg was increased substantially by dolomitic but tended to be decreased by calcitic. Limestone with 4% Mg was required to increase leaf Mg. Mg deficiency in commercial production has been caused by excessive calcitic application. Meaningful increases were obtained in leaf Ca and Mg, as were decreases in leaf Mn indicating increased soil pH, within 2–3 months after limestone application. Limestone types ...