Damage, Occurrence, and Optimal Control Period of Eurytoma maslovskii Affecting Japanese Apricot (Prunus mume) Fruits in Jeonnam Province

Abstract

Fruit drop due to Eurytoma maslovskii infestations of Japanese apricot (Prunus mume) is a serious economic issue in most parts of Jeonnam Province, with the exception of the coastal areas such as Wando, Shinan, Yeosu, and Muan. The average incidence of fruit drop was 67% in 2013 and 33.3% in 2014. E. maslovskii larvae overwinter inside the pits of Japanese apricots. Larval survival rates decrease to less than 30% after a rainy summer season. The eggs are long oval of 0.68 mm, 0.29 mm and ivory white. Mature larva is of 6.56 mm, 3.18 mm. Free pupa are black, adult females and males of 6.97 mm, 4.90 mm lengths, respectively, while the ovipositor is 0.64 mm in length. Adult emergence occurs from early April to early May, when Japanese apricot fruits are from 4 mm to 17 mm in diameter. Adults persist for 13.5 d after emergence, and the sex ratio of females to males was found th be 45.9:54.1. Although up to four eggs may be oviposited per fruit, only one larva will ultimately survive, ans the larvae are cannibalistic. The period during which E. maslovskii is able to oviposit on Japanese apricots only lasts from mid-to late April (fruit diameter: 12~16 mm). When the diameter of the fruit is >16 mm, the pit of the Japanese apricot hardens and larvae have difficultly penetrating the stone. Therefore, the most effective method of controlling this pest is to spray orchards with a control agent 2~3 times, at 5 d intervals, beginning in mid-April.

Temperature-Dependent Development of the Post-Diapause Periods of the Apricot Seed Wasp Eurytoma maslovskii (Hymenoptera: Eurytomidae): An Implication for Spring Emergence Prediction Models

“…ansu Max., and peach Prunus persica (L.) Batsch [ 3 ]. Since its first occurrence in 1979 [ 4 ], E. maslovskii has become a destructive pest in the main apricot production area in Korea [ 3 , 5 ]. In China, the occurrence of E. maslovskii has been confirmed in Hebei [ 6 ], Liaoning, Chaoyang [ 2 ], Zhejiang [ 7 ], and Shandong [ 8 ].…”

“…In China, the occurrence of E. maslovskii has been confirmed in Hebei [ 6 ], Liaoning, Chaoyang [ 2 ], Zhejiang [ 7 ], and Shandong [ 8 ]. The fruits infested by E. maslovskii result in the non-development of the flesh leading to a loss of apricot fruit production of 33.3–67% [ 5 ], and up to 80% of the crop being severely infested [ 9 ].…”

“…Eurytoma maslovskii adults emerge in spring, from early April to early May, coinciding with the fruiting periods of apricot trees [ 5 ]. The female uses her approximately 5 mm long ovipositor to deposit eggs into the soft nucleus part of the developing seed [ 3 ].…”

“…The female uses her approximately 5 mm long ovipositor to deposit eggs into the soft nucleus part of the developing seed [ 3 ]. Although several eggs may be deposited within a fruit, only one larva is able to ultimately develop in each seed [ 5 ]. The entire larval stage consumes the nucleus within the endocarp for development.…”

Soil microbial communities of Japanese apricot (Prunus mume) orchard under organic and conventional management

“…However, organic farms' Japanese apricot fruit damage rate caused by Eurytoma maslovskii was measured to be 36.7% in 2017 and 23.3% in 2018, both of which were significantly higher than conventional farms' fruit damage rate. Choi et al [40] reported that the overall Japanese apricot fruit damage rate caused by Eurytoma maslovskii was 67.3% in 2013 and 33.3% in 2014 in Jeonnam Province. It soared to 90% in one of the most serious cases in the past [41].…”