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We developed new integrated pest management programs for eastern U.S. peaches with minimal use of organophosphates. From 2002-2005, we assessed the ecological impacts of these reduced-risk programs versus grower standard conventional programs that still relied primarily on the use of organophosphorous and carbamate insecticides. Using a split-plot design replicated at four commercial Pennsylvania peach orchards, we quantified pesticide rates, environmental impact, and arthropod community response. We used Environmental Impact Quotient (EIQ) analysis based on the growers' pesticide records from each orchard to calculate seasonal cumulative EIQ field ratings for all years. Ecological effects of the reduced-risk and conventional program were also measured as the abundance and diversity of nontarget arthropod predators, parasitoids, and selected pest taxa. Pesticide inputs and EIQ values were substantially lower in reduced-risk programs compared with conventional spray programs. Arthropod arrays differed significantly between pest management programs: most beneficial predator and parasitoid taxa were positively associated with the reduced-risk program and negatively associated with the standard grower program. Regardless of the pest management program, we observed significant differences in species arrays in the peach tree canopy compared with the ground cover of the orchards, but the arthropod community did not differ among the field sites or based on distance from the edge of the orchard. We conclude that reduced-risk programs not only provide control comparable with that of conventional programs, but they also reduce negative environmental effects while conserving key arthropod biological control agents within eastern U.S. peach orchards. [ABSTRACT FROM AUTHOR]

The article obtains complete genome sequences of 7 Canadian Plum pox virus (PPV) isolates from infected peach, plum and flowering almond and to compare them with other complete sequences reported in Europe and U.S. with the longer term of using the information for managing PPV in Canada. Comparison on the nucleotide sequences and amino acids of 7 isolates revealed that Canadian isolates fall into 2 subgroups, I and II, where subgroup I were from plum and II from peach and flowering almond.

The development of rust epidemics caused by Tranzschelia discolor on leaves and stems of cling peach was studied in California orchards. Sporulating stems lesions were only detected from late March until July in 1997 and 1998. When rust was present in the fall, the quadratic equation Y = -82.51 + 1.97JD - 0.01JD² using Julian day (JD) described the incidence of sporulating lesions on stems of cv. Andross (R² = 0.73; P ≤ 0.001) in the following spring season. Late-season rust epidemics occurred in 1996 and 1997. Incidence of rust on leaves of cvs. Andross and Ross was <10% from April through July and 80 to 100% by October/November. In 1998, early-season epidemics developed with disease incidence at 28 to 56% by July/August in two cv. Andross orchards. No disease was observed during the 1999 growing season. Using linear regression analysis, logistic and exponential models best described the development of disease in 1996 and 1997, respectively. In contrast, the monomolecular model best described the disease in 1998. In an analysis of variance comparing disease progress curves on cv. Andross from 1996 to 1998, no significant differences in area under the disease progress curve and p were observed, whereas y[sub max] was significantly different (P < 0.001). A repeated measures analysis indicated that in a cv. Andross orchard the year of the disease progress curve, time of sampling, and their interaction were highly significant (P < 0.01). This indicated a distinct difference between early- and late-season epidemics. Earlyseason development of rust on leaves occurred in years with ≥117.3 mm of total precipitation and maximum temperatures of ≤30.2°C in April to June. [ABSTRACT FROM AUTHOR]

In greenhouse and field studies, rust on cling peach caused by Tranzschelia discolor was significantly reduced on leaves and fruit compared with that on controls by foliar applications of wettable sulfur, an agricultural oil, a substituted aromatic (e.g., chlorothalonil), as well as benzimidazole (e.g., benomyl, thiophanate-methyl), sterol biosynthesis inhibiting (e.g., myclobutanil, propiconazole, tebuconazole), and strobilurin (e.g., azoxystrobin) fungicides. The timing of treatments was a significant factor in reducing disease in most trials. Protective programs using wettable sulfur, tebuconazole, or azoxystrobin applied after stem lesion detection (ASLD) and before forecasted rains were highly effective. In the most effective programs for managing the disease, however, these fungicides were applied after stem lesion detection and occurrence of rainfall. Under highly conducive field environments for disease, single applications of azoxystrobin or tebuconazole at ASLD were significantly more efficacious than sulfur. Dormant treatments of liquid lime sulfur, chlorothalonil, or thiophanate-methyl/agricultural oil, however, were ineffective in reducing the disease during the subsequent spring and summer seasons. This is the first management program for rust on cling peach that utilizes inoculum and precipitation events to optimize timing of fungicide applications. [ABSTRACT FROM AUTHOR]

Presents a report of sour rot of California peaches and nectarines caused by yeasts. Observation of decay of nectarine and peach fruits from the Tulare orchard; Fruit decay lesion symptoms; Identification of three yeasts present on the fruits; Conduction of sporulation and culturing on potato dextrose agar; Reproduction of the decay and leak symptoms; Confirmation of the role of yeasts in the rotting of the fruits.