Evaluation of the Parasitism Capacity of a Thelytoky Egg Parasitoid on a Serious Rice Pest, Nilaparvata lugens (Stål)

SIMPLE SUMMARY: Nilaparvata lugens (Stål) (BPH) is a major rice pest that severely reduces global rice production. Egg parasitoids can eliminate BPH eggs and effectively reduce the damage caused by BPH. In this study, we assessed the parasitism capacity of a strain of Pseudoligosita yasumatsui reproduced via thelytoky, which was compared to Anagrus nilaparvatae, one of the dominant egg parasitoid of rice planthoppers. The results showed that both egg parasitoids preferred parasitizing the fertilized BPH eggs and that parasitization mostly occurred during the daytime, notably during 07:00–15:00. The parasitism capacity of this strain of P. yasumatsui was slightly higher than that of A. nilaparvatae. Both the egg parasitoids preferred parasitizing 1–3-day-old BPH eggs. However, the parasitism of this strain of P. yasumatsui on older BPH eggs was better than that of A. nilaparvatae. The findings support the use of P. yasumatsui to control the rice pest N. lugens. ABSTRACT: Pseudoligosita yasumatsui and Anagrus nilaparvatae are both egg parasitoids of the brown planthopper, Nilaparvata lugens (Stål) (BPH). In this study, we obtained a stable strain of P. yasumatsui reproduced via thelytoky through indoor rearing and screening. We assessed the parasitism capacity of this strain on eggs of N. lugens by comparing the parasitism preference and circadian rhythm of this strain to that of A. nilaparvatae, which is proved as the dominant egg parasitoid species of BPH in rice fields. The findings indicated that both egg parasitoids could parasitize fertilized and unfertilized BPH eggs, however, with a significant preference for fertilized eggs. The daily parasitization volume of P. yasumatsui was slightly higher than that of A. nilaparvatae. Both egg parasitoids preferred parasitizing 1–3-day-old BPH eggs, but the parasitism amount of 5–6-day-old BPH eggs by P. yasumatsui is higher than that by A. nilaparvatae. The parasitism events of both species of egg parasitoid wasps occurred primarily from 7:00–15:00 and the parasitism amount at night accounted for less than 15% of the total amount. The results indicate that this strain of P. yasumatsui reproduced via thelytoky could be valuable for rice planthopper control.