Harvest load gradesheet data for pistachios 2007-2017

The navel orangeworm, Amyelois transitella, is the primary pest of pistachios in California. The first A. transitellaoutbreak of the twenty-first century occurred in 2007 and a total of five outbreaks occurred between 2007-2017 (total insect damage > 1%). This study used processor information to identify the nut factors associated with the outbreaks. Processor grade sheets were used to explore the relationship between the variables time of harvest, percent nut split, percent nut dark staining, percent nut shell damage and percent adhering hull for Low Damage (82,537 loads) and High Damage years, (92,307 loads). Total insect damage (±SD) for the Low Damage years averaged 0.005±0.01 and in High Damage years was three times higher, 0.015±0.02. In Low Damage years the strongest correlation was between total insect damage and two variables, percent adhering hull and dark stain (0.25, 0.23) while in High Damage years the correlation between total insect damage and percent dark stain was the highest (0.32) followed by percent adhering hull (0.19). The linkage of these nut factors to insect damage suggests that outbreak prevention depends on early identification of premature hull split/breakdown in addition to the traditional emphasis on treating the standing population of A. transitella.

脐果蛀蛾（navel orangeworm，*Amyelois transitella*）是美国加州开心果的主要害虫。21世纪该虫的首次暴发发生于2007年，2007至2017年间共计发生5次暴发，总虫害占比超过1%。本研究依托坚果加工厂的相关数据，筛选与该虫暴发相关的坚果品质因子。研究采用加工厂分级质检单据，分别针对低虫害年份（共82537车货量）与高虫害年份（共92307车货量），分析收获期、坚果开裂率、坚果暗污率、坚果壳破损率及果壳黏附率这几项变量间的关联关系。低虫害年份的总虫害占比（±标准差，SD）均值为0.005±0.01，高虫害年份的总虫害占比则为前者的3倍，达0.015±0.02。低虫害年份中，总虫害占比与果壳黏附率、暗污率的相关性最强，相关系数分别为0.25与0.23；而高虫害年份中，总虫害占比与暗污率的相关性最高（0.32），其次为果壳黏附率（0.19）。上述坚果品质因子与虫害占比的关联关系表明，该虫的暴发防控除需延续传统的针对田间现存种群的防治手段外，还应提前识别过早的果壳开裂或破损情况。