Biological Control: A Major Component of the Pest Management Program for the Invasive Coconut Scale Insect, Aspidiotus rigidus Reyne, in the Philippines.

The coconut scale insect, Aspidiotus rigidus Reyne, caused a major pest outbreak in coconut plantations and stands in the Southern Tagalog region of Luzon Island in the Philippines between 2010 and 2015. To determine if parasitism by Comperiella calauanica Barrion, Almarinez and Amalin, a native encyrtid, could have been a factor in the eventual management of the outbreak by 2015, we estimated and assessed its parasitization levels on A. rigidus colonies on field-collected samples from selected points in three provinces in the Southern Tagalog Region across three sampling periods. We observed that C. calauanica consistently occurred only in areas where A. rigidus populations occurred, with high parasitization levels in the Southern Tagalog sites from 2014 to 2015. Results of correlation and regression of total scale count against parasitized scale count suggest putative host density-dependent parasitism by C. calauanica in the field. A marked decrease in the abundance of A. rigidus was recorded concurrently with visually observable recovery of coconut trees from the third quarter of 2014 up to the second quarter of 2016. Similar results of significant reduction in A. rigidus populations concurrent with high percent parasitization by mass-reared and released C. calauanica were found in the Zamboanga Peninsula from 2018 to 2020. Our findings and observations altogether suggest that host-specific parasitization by C. calauanica effected biological control, which may have contributed to the eventual management of the A. rigidus outbreak in the Southern Tagalog Region, and also in the Zamboanga Peninsula where similar recovery of coconut trees were observed within a year after inoculative releases of C. calauanica.

Review of the genus Exopholis Motschulsky, 1859 (Coleoptera: Scarabaeidae: Melolonthinae: Leucopholini) in the Philippines.

Motschulsky (1859), a Russian Imperial Army Colonel and entomologist, established the genus Exopholis, described E. birmannica and transferred Melolontha hypoleuca Wiedemann, 1819 to it. Brenske (1896) described Exopholis philippinica from the "Philippinen" from a single female specimen. Dalla Torre (1912), listed eight species under the genus Exopholis Motschulsky, 1859 from South East Asia: E. hypoleuca (Weidemann, 1819) (Myanmar, Malaysia, Borneo, Java, Sumatra, Nias, Ambon), E. costata (Burmeister, 1855) (Java, Nias), E. birmanica Motschulsky, 1859 (Myanmar), E. lacordairei Waterhouse, 1867 (Borneo), E. pinguis Lansberge, 1879 (Sumatra), E. brenskei Nonfried, 1891, E. borneensis Brenske, 1894 (both from Borneo) and E. philippinica Brenske, 1896 (Philippines). This paper aims to review the taxonomy of Exopholis from the Philippines. Specifically, to focus on the diagnosis of Exopholis philippinica and its geographic distribution.

Assessing Potential Impact of Bt Eggplants on Non-Target Arthropods in the Philippines.

Studies on potential adverse effects of genetically engineered crops are part of an environmental risk assessment that is required prior to the commercial release of these crops. Of particular concern are non-target organisms (NTOs) that provide important ecosystem services. Here, we report on studies conducted in the Philippines over three cropping seasons with Bt eggplants expressing Cry1Ac for control of the eggplant fruit and shoot borer (EFSB), Leucinodes orbonalis, to examine potential effects on field abundance, community composition, structure and biodiversity of NTO's, particularly non-target arthropod (NTA) communities. We document that many arthropod taxa are associated with Bt eggplants and their non-Bt comparators and that the number of taxa and their densities varied within season and across trials. However, we found few significant differences in seasonal mean densities of arthropod taxa between Bt and non-Bt eggplants. As expected, a lower abundance of lepidopteran pests was detected in Bt eggplants. Higher abundance of a few non-target herbivores was detected in non-Bt eggplants as were a few non-target beneficials that might control them. Principal Response Curve (PRC) analyses showed no statistically significant impact of Bt eggplants on overall arthropod communities through time in any season. Furthermore, we found no significant adverse impacts of Bt eggplants on species abundance, diversity and community dynamics, particularly for beneficial NTAs. These results support our previous studies documenting that Bt eggplants can effectively and selectively control the main pest of eggplant in Asia, the EFSB. The present study adds that it can do so without adverse effects on NTAs. Thus, Bt eggplants can be a foundational component for controlling EFSB in an Integrated Pest Management (IPM) program and dramatically reduce dependence on conventional insecticides.