Profile of Fork-Tailed Bush Katydid (Orthoptera: Tettigoniidae) Feeding on Fruit of Clementine Mandarins

Herbivory by European Earwigs (Forficula auricularia; Dermaptera: Forficulidae) on Citrus Species Commonly Cultivated in California

Agricultural plant species differ in susceptibility to herbivores; therefore, identifying natural resistances or tolerances to pests can be leveraged to develop preventative, integrated pest management approaches. While many Citrus species are grown in California, most pest management guidelines are based upon research conducted on navel oranges [Citrus sinensis (L.) Osbeck; Sapindales: Rutaceae]. A recent study has established European earwigs (Forficula auricularia L.; Dermaptera: Forficulidae) as herbivores of young navel orange fruit, causing damage ranging from small bite marks to large chewed holes. It is unknown whether earwigs damage fruit of other citrus species. We conducted field experiments in which we caged earwigs to branch terminals bearing young fruit to explore potential differences in susceptibility of Citrus species to European earwigs. Specifically, we tested whether three species, navel oranges, clementines (C. clementina hort. ex Tanaka), and true mandarins (C. reticulata Blanco) exhibit differences in: 1) feeding deterrence to earwigs; 2) suitability as food for earwigs; 3) preferential abscission of damaged fruit; and 4) healing of damaged fruit. Earwigs caused heavy damage on navel orange and clementine fruit, whereas heavy damage was rare on true mandarin fruit. There was little evidence of preferential abscission of damaged fruit or healing of seriously damaged fruit. Consequently, several heavily damaged navel orange and one clementine fruit were retained to harvest and developed large scars. Overall, we found that Citrus fruit vary in their susceptibility to earwigs, and pest management strategies for earwigs should be refined to consider their varying effects on different Citrus species.

Characterizing Herbivory by European Earwigs (Dermaptera: Forficulidae) on Navel Orange Fruit with Comparison to Forktailed Bush Katydid (Orthoptera: Tettigoniidae) Herbivory

In establishing Integrated Pest Management (IPM) plans for understudied pests, it is crucial to understand the nature of their herbivory and resulting damage. European earwig (Forficula auricularia L.; Dermaptera: Forficulidae) densities are increasing in citrus orchards in Central California. Field observations suggest that earwigs feed on young, developing citrus fruit, but this hypothesis had not been examined with formal experimentation. Forktailed bush katydid nymphs (Scudderia furcata Brunner von Wattenwyl; Orthoptera: Tettigoniidae) are well-known citrus herbivores that feed on young citrus fruit, and it is possible that earwig damage may be misdiagnosed as katydid damage. Here we report findings from two field experiments in navel oranges (Citrus sinensis (L.) Osbeck; Sapindales: Rutaceae) that together tested: (1) whether earwigs damage young citrus fruit; (2) whether the amount of damage earwigs generate differs across developmental stage or sex of adult earwigs; (3) the window of time during which fruit are most sensitive to earwig damage; (4) whether damaged fruit are retained to harvest; and (5) the resulting damage morphology caused by earwigs relative to katydids. Earwigs, particularly nymphs, chewed deep holes in young citrus fruit from 0 to 3 wk after petal fall. Fruit damaged by earwigs were retained and exhibited scars at harvest. The morphology and distribution of scars on mature fruit only subtly differed between earwigs and katydids. This study establishes that earwigs can be direct pests in mature navel orange trees by generating scars on fruit and likely contribute to fruit quality downgrades.

Evaluating the Quality of Ecoinformatics Data Derived From Commercial Agriculture: A Repeatability Analysis of Pest Density Estimates

Each year, consultants and field scouts working in commercial agriculture undertake a massive, decentralized data collection effort as they monitor insect populations to make real-time pest management decisions. These data, if integrated into a database, offer rich opportunities for applying big data or ecoinformatics methods in agricultural entomology research. However, questions have been raised about whether or not the underlying quality of these data is sufficiently high to be a foundation for robust research. Here I suggest that repeatability analysis can be used to quantify the quality of data collected from commercial field scouting, without requiring any additional data gathering by researchers. In this context, repeatability quantifies the proportion of total variance across all insect density estimates that is explained by differences across populations and is thus a measure of the underlying reliability of observations. Repeatability was moderately high for cotton fields scouted commercially for total Lygus hesperus Knight densities (R = 0.631) and further improved by accounting for observer effects (R = 0.697). Repeatabilities appeared to be somewhat lower than those computed for a comparable, but much smaller, researcher-generated data set. In general, the much larger sizes of ecoinformatics data sets are likely to more than compensate for modest reductions in measurement precision. Tools for evaluating data quality are important for building confidence in the growing applications of ecoinformatics methods.

Commodity risk assessment of Citrus L. fruits from South Africa for Thaumatotibia leucotreta under a systems approach

The European Commission requested to the EFSA Panel on Plant Health to evaluate a dossier from South Africa where the application of the systems approach to mitigate the risk of entry of the false codling moth, Thaumatotibia leucotreta (Lepidoptera: Tortricidae), into the EU when trading citrus fruits is explained. After collecting additional evidence from the Department of Agriculture, Land Reform and Rural Development of South Africa, and reviewing the published literature, the Panel performed an assessment on the likelihood of pest freedom for T. leucotreta on citrus fruits at the point of entry in the EU considering the proposed systems approach. An expert judgement is given on the likelihood of pest freedom following the evaluation of the risk mitigation measures on T. leucotreta, including any uncertainties. There are three options (i.e. A, B and C) within the systems approach followed in South Africa that differentiate mainly in the sampling intensity in the field and the packing house as well as in temperature conditions during shipment. Therefore, three independent elicitations were conducted, one for each option. The main uncertainties were: (1) whether sampling once per orchard is representative for subsequent harvests (within 4 weeks) from the same orchard; (2) the correct implementation of the temperature regimes during shipment; (3) the mortality rate in fruit estimated for the different temperature regimes. The Expert Knowledge Elicitation indicated with 95% certainty that 9,182 out of 10,000 pallets for option A, 8,478 out of 10,000 pallets for option B, and 9,743 out of 10,000 pallets for option C will be free from T. leucotreta. In light of the additional information provided by South Africa once the elicitations were performed, it became apparent that the setting temperature during shipment was not achieved in 12 out of 14 cases of interceptions. Therefore, there is increased uncertainty on pest freedom. The Panel identified the weaknesses associated with the risk mitigation measures in the systems approach and made recommendations that could increase its effectiveness.

Commodity risk assessment of Citrus L. fruits from Israel for Thaumatotibia leucotreta under a systems approach

The European Commission requested EFSA Panel on Plant Health to evaluate a dossier from Israel in which the application of the systems approach to mitigate the risk of entry of Thaumatotibia leucotreta to the EU when trading citrus fruits is described. After collecting additional evidence from the Plant Protection and Inspection Services (PPIS) of Israel, and reviewing the published literature, the Panel performed an assessment on the likelihood of pest freedom for T. leucotreta on citrus fruits at the point of entry in the EU considering the Israelian systems approach. An expert judgement is given on the likelihood of pest freedom following the evaluation of the risk mitigation measures on T. leucotreta, including any uncertainties. The Expert Knowledge Elicitation indicated, with 95% certainty that between 9,863 and 10,000 citrus fruits per 10,000 will be free from this pest. The Panel also evaluated each risk mitigation measure in the systems approach and identified any weaknesses associated with them. Specific actions are identified that could increase the efficacy of the systems approach.