Host stage preference and demographic parameters of Leptomastix dactylopii (Hymenoptera: Encyrtidae) on vine mealybug Planococcus ficus (Hemiptera: Pseudococcidae)

Abstract

Background This study was conducted to investigate host stage preference and demographic parameters of the parasitoid species, Leptomastix dactylopii Howard (Hymenoptera: Encyrtidae), the parasitoid of vine mealybug Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), an important pest in vineyards in many countries. Results The results revealed that L. dactylopii was not able to develop on the 1st and 2nd nymphal instars of P. ficus and preferred female mealybugs as the host to the 3rd nymphal instar. Hind tibia length and head capsule width of both female and male parasitoids emerged from the mummies of mealybugs parasitized in the female stage were greater than the values of the parasitoids emerged from the mummies of mealybugs parasitized in the 3rd nymphal instar. Demographic parameters of the parasitoid were calculated with the use of development and reproduction data obtained from life table of L. dactylopii. The intrinsic rate of increase was determined as (r = 0.1527 d−1), finite rate of increase as (λ = 1.1650 d−1), net reproductive rate as (R0 = 46.0667 offspring), and mean generation time as (T0 = 25.0830 d). Conclusions It was concluded that L. dactylopii was able to develop, especially in the female and in the 3rd nymphal instar of P. ficus and could be used for biological control of the vine mealybug.

Leptomastix dactylopii Howard (Hymenoptera: Encyrtidae): parasitoid of mealybugs (Hemiptera: Pseudococcidae)

“…Leptomastix dactylopii is thought to be native to South America and Africa (Bartlett 1978;Anga and Noyes, 1999) but later spread around the world (Figure 1). It has been frequently used as a biocontrol agent against mealybugs in the Middle East, Europe, United States, Pakistan, India, and Australia (Smith et al 1988;Noyes and Hayat 1994;Cocco et al 2021;Muştu et al 2022).…”

“…Females (Figure 2) lay only one egg per host individual (Yang and Sadof 1997;Marras et al 2016) and prefer large size hosts including third and fourth instar nymphs (de Jong and van Alphen 1989; Muştu et al 2022). Upon finding a suitable host, a female exhibits the behavior of examination, probing and oviposition (Chong and Oetting 2007).…”

“…Parasitized mealybugs turn brown in color and their bodies become bloated (Figure 3 top row). Muştu et al (2022) reported that Leptomastix dactylopii female and male developmental time (egg to adult) is 16 and 15 days, respectively, when developing in third instar nymphs and 17 and 16 days, respectively, when developing in females of Planococcus ficus. Battaglia et al (1996) reported a developmental duration for female and male Leptomastix dactylopii at 18 and 16 days, respectively.…”

“…Leptomastix dactylopii adults emerge by chewing an exit hole in the mummified mealybug (Figure 4 top row). The wasp completes its life cycle in the host within approximately 3-4 weeks depending on the temperature and size of mealybug (Muştu et al 2022). At 25ºC (77°F), Leptomastix dactylopii can complete a generation in 16-18 days (Battaglia et al 1996).…”

“…At 25ºC (77°F), Leptomastix dactylopii can complete a generation in 16-18 days (Battaglia et al 1996). According to Muştu et al (2022), the total life span of parasitoid females and males in Plancoccous citri or Plancoccus ficus averaged 41 and 38 days, respectively. The adult is small {2-3 mm (~1/8 in)}, yellowish brown, and distinguishable by its long antennae which are darker in color and almost same length as the body (Anga and Noyes 1999).…”