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One of the major challenges facing citrus integrated pest management (IPM) in California is the recent, sharp increase in the acreage of mandarins being planted. The current citrus IPM guidelines have been established from years of experiments and experience in oranges, with no specific guidelines for mandarins. In the absence of research into key arthropod pest effects in mandarins, the assumption that the pest management practices for oranges appropriately transfer for optimal production in mandarins has not been tested. We used a data mining or 'ecoinformatics' approach in which we compiled and analyzed production records collected by growers and pest control advisors to gain an overview of direct pest densities and their relationships with fruit damage for 202 commercial groves, each surveyed for 1–10 yr in the main production region of California. Pest densities were different among four commonly grown species of citrus marketed as mandarins (Citrus reticulata , C. clementina , C. unshiu , and C. tangelo) compared with the standard Citrus sinensis sweet oranges, for fork-tailed bush katydids (Scudderia furcata Brunner von Wattenwyl [Orthoptera: Tettigoniidae]), and citrus thrips (Scirtothrips citri Moulton [Thysanoptera: Thripidae]). Citrus reticulata had notably low levels of fruit damage, suggesting they have natural resistance to direct pests, especially fork-tailed bush katydids. These results suggest that mandarin-specific research and recommendations would improve citrus IPM. More broadly, this is an example of how an ecoinformatics approach can serve as a complement to traditional experimental methods to raise new and unexpected hypotheses that expand our understanding of agricultural systems. [ABSTRACT FROM AUTHOR]

Abstract: Two experiments were conducted to assess the relationship between alternate bearing, flowering, fruit set, and fruit growth in mature ‘Hass’ avocado (Persea americana Mill.) in Irvine, California. In the first experiment, trees were grown on four clonal rootstocks (‘Thomas’, ‘Topa Topa’, ‘Duke 7’, or ‘D9’), and data collected on yield, number of fruit per tree, average fruit weight, and the timing and duration of flowering over five seasons. In the second experiment, ‘Hass’ trees were grown on ‘Duke 7’ rootstock and data collected on the rate of fruit retention and fruit volume growth over three years. In Experiment 1, the trees exhibited “on” and “off” years in most cropping cycles. Heavy yields were associated with a higher number of fruit per tree, lower average fruit weight, and early and longer periods of flowering. Although yield varied among rootstocks, especially in heavy crop load years, trees growing on different rootstocks had similar cropping patterns. In Experiment 2, fruit abscission varied over years, but rates of volume increase were similar over years. Low yields in ‘Hass’ avocado trees appear to be related to later and shorter flowering periods and fewer and larger fruit at harvest. [Copyright &y& Elsevier]