English walnut (Juglans regia) producers in California compete with many insect and disease pests to produce an acceptable crop. Traditional control strategies work reasonably well for most pests. However, environmental concerns, loss of certain pesticides and new or impending regulations threaten the use of many traditional techniques for control of many of the pests. Codling moth (Cydia pomonella), walnut husk fly (Rhagoletis completa), and walnut aphid (Chromaphis juglandicola) are the major insects that affect California walnut production. Control strategies that use integrated pest management programs, beneficial insects, mating disruption, insect growth regulators, improved monitoring techniques and precise treatment timing based on the insect's life cycle are leading edge techniques currently available for insect control in walnuts. Major diseases include walnut blight (Xanthomonas campestris pv. juglandis), crown gall (Agrobacterium tumefaciens) and crown and root rot (Phytophthora spp). Both copper resistant and copper sensitive strains of the walnut blight bacterium are best controlled with combinations of copper bactericides and maneb instead of copper materials alone. A new computer model, Xanthocast, used to forecast the need for walnut blight treatment is under evaluation. Crown gall is managed using a preplant biological control agent and a heat treatment to eradicate existing galls. Phytophthora crown and root rot is dealt with primarily by site selection, irrigation management and rootstock selection.
William H. Olson and Richard P. Buchner
Michael J. Willett, Lisa Neven, and Charles E. Miller
Phytosanitary restrictions are increasingly a factor in the ability of U.S. tree fruit exporters to gain and maintain access to worldwide markets. Under international trade rules, these restrictions must be based on specific guidelines, including an assessment of whether the proposed quarantine pest is likely to establish and spread under the climatic conditions of the importing country. Given the interest in and growth of temperate fruit production in the tropics, countries in the region (such as Taiwan, Columbia, Indonesia, and Thailand) have begun to impose a range of quarantine restrictions aimed at preventing the introduction of temperate zone pests. Apples (Malus ×domestica) are regulated in certain tropical/subtropical countries, such as Taiwan, for the presence of codling moth (CM; Cydia pomonella) in spite of reports in the literature that the distribution of CM is theoretically limited by daylength and chilling requirements to temperate regions. This work provides background as to why CM has been identified as a potential pest of quarantine concern in some low latitude countries; describes an approach used to validate worldwide CM distribution reports, providing additional information to allow for the revision of CM distribution maps; and demonstrates how accurate information regarding pest species distribution reports can aid in establishing an argument of ecological nonadaptability in the pest risk analysis process. Currently, a report of CM in Peru remains the only account of this pest's presence in low latitude countries that could not be refuted by the approach described here.
Abhava M. Dandekar, Gale H McGranahan, Sandra L. Uratsu, Charles Leslie, J. Steven Tebbets, and Patrick V. Vail
Insecticidal crystal protein fragments (ICPFs) of Bacillus thuringiensis (Bt) encoded by cryIA(c) gene were shown in diet incorporation studies to be lethal to codling moth (CM; Cydia pomonella) the key insect pest for walnut. However transformed walnut tissues expressing cryIA(c) with Bt codon usage patterns and native DNA sequence revealed very low levels of expression in planta. To correct this problem synthetic versions of one of these genes, cryIA(c) was used to transform walnut tissue. A total of 61 individual transgenic embryo lines were obtained. 34% of these lines (21/61) were high expressors (“class A”) demonstrating 80 to 100% mortality of first in star CM larvae and displaying no further larval development. Twelve clones (20%) were designated “class B” and these showed a marked retardation of larval development and a mortality between 40 to 79%. Embryos from the remaining 28 lines designated “class C” (46%). although transformed, were indistinguishable from the control (untransformed embryos) and showed a mortality of 0 to 39%.
Krista C. Shellie, Lisa Neven, and Steve Drake
Phytosanitary restrictions for insect pests can interfere with the marketing of fresh sweet cherries (Prunus avium L.). The objective of this research was to compare the quality of controlled atmosphere temperature treated (CAT) sweet cherries to methyl bromide fumigated cherries and non-heated, non-fumigated control fruit. Two CAT doses were evaluated: a 25-min exposure to 47 °C (117 °F) that heated the cherry center to 46 °C (115 °F), and a 40-min exposure to 45 °C (113 °F) that heated the cherries to a center temperature of 44 °C (111 °F). These heat doses approximated a heat dose that provides quarantine security against codling moth (Cydia pomonella Lw.) and western cherry fruit fly (Rhagoletis cingulata Lw.). An atmosphere of 1 kPa oxygen and 15 kPa carbon dioxide was established inside the treatment chamber for 21 min prior to heating. The influence on fruit quality of hydrocooling prior to the CAT treatment, cooling after treatment, and 2 weeks of cold storage after treatment in air or controlled atmosphere was evaluated. Each CAT dose was replicated four times using freshly harvested, `Bing' sweet cherries acquired from similar grower lots. Quality attributes evaluated included: stem and fruit color, firmness, soluble solids concentration, titratable acidity, decay, and sensory evaluations. Hydrocooling prior to treatment, cooling method after heating and storage atmosphere had no significant influence on cherry quality after cold storage. The stem color of fumigated cherries was less green after storage than CAT treated cherries or untreated, control cherries. Cherries heated for 25 min were rated after cold storage by untrained panelists as similar to non-heated, non-fumigated control fruit. Heated cherries and methyl bromide fumigated cherries were less firm after cold storage than control fruit.
Mark A. Williams, John G. Strang, Ricardo T. Bessin, Derek Law, Delia Scott, Neil Wilson, Sarah Witt, and Douglas D. Archbold
Although the interest in and production acreage of organic fruit and vegetables has grown in recent years, there are questions about the viability of perennial crops such as apple (Malus ×domestica) in an organic system in Kentucky because of the long, hot, and humid growing season. Thus, the objective of this project was to assess the severity of the challenges to organic apple production in Kentucky. A high-density, organic apple orchard was established in 2007 in the University of Kentucky Horticultural Research Farm in Lexington. The orchard of apple scab (Venturia inaequalis)–resistant ‘Redfree’, ‘Crimson Crisp’, and ‘Enterprise’ trees on ‘Budagovsky 9’ (B.9) rootstock, trained in a vertical axis system, was managed using organically certified techniques and materials for disease and insect control since its inception. Tree growth, tree and fruit injury from insect pests and diseases, and yield over the period 2011–13 were studied. Periodic, shallow cultivation kept the ground beneath the trees free of vegetation once the lower limbs were pulled up and away from the path of the equipment. Vole (Microtus sp.) damage was a continuing problem despite the use of trunk guards and cultivation to remove habitat around the trees. Total fruit yield ranged from 1.2 to 8.1 kg/tree across years and cultivars, with the marketable proportion of the total yield averaging 68% for Redfree and 43% for Crimson Crisp and Enterprise over the 3-year period. The unmarketable fruit exhibited a high incidence of plum curculio (Conotrachelus nenuphar) damage, with generally less damage from codling moth (Cydia pomonella) and sooty blotch (Glosodes pomigena)/flyspeck (Schizathyrium pomi). In addition, in two of the three seasons, ‘Crimson Crisp’ and ‘Enterprise’, which were harvested at later calendar dates then ‘Redfree’, had significant levels of powdery mildew (Podosphaera leucotricha) injury, ‘Enterprise’ had significantly greater bitter rot (Glomerella cingulata), and ‘Crimson Crisp’ showed fruit and foliar damage from cedar apple rust (Gymnosporangium juniperi-virginianae). Because ‘Redfree’ was the only cultivar with an acceptable marketable proportion of the fruit crop, the use of early ripening disease-resistant apple cultivars may have the greatest potential for successful organic apple production in Kentucky and the surrounding region.
early harvest date ≈3 weeks before ‘Chandler’ ( Table 1 ). The cultivar is resistant to codling moth ( Cydia pomonella ). Leafing occurs 2 weeks before ‘Chandler’. Male and female flowers are borne mostly on lateral shoots. Lateral buds are 75% fruitful
Ioannis Manthos and Dimos Rouskas
easy hull dehiscence (similar to ‘Chandler’ and ‘Hartley’) low sunburn susceptibility of the hull, intermediate susceptibility to the codling moth ( Cydia pomonella L.), and a very low susceptibility to walnut blight ( Χanthomonas campestris ) ( Table
Richard L. Bell and Tom van der Zwet
psylla ( Cacopsylla pyricola Föerster) and control measures are necessary. Observations indicated that fruit of ‘Sunrise’ are also susceptible to damage by codling moth [ Cydia pomonella (L.)], European pear sawfly ( Hoplocampus brevis Klug), and brown
Thomas Sotiropoulos and Nikolaos Koutinas
observations, ‘Eris’ has the same degree of resistance with the cultivar Red Chief to the most important pests and diseases such as codling moth ( Cydia pomonella L.), apple leaf miners ( Lyonetia clerkella L.), european red mite ( Panonychus ulmi L.), apple
Lisa G. Neven
quarantine concern in sweet cherries grown in the Pacific Northwest are codling moth (CM) ( Cydia pomonella ) and Western cherry fruit fly (WCFF) ( Rhagoletis indifferens ). Codling moth is a lesser concern on sweet cherries, because sweet cherries are known