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Grapholita molesta (Busck) is a menacing pest of fruit trees worldwide. A mixture of glucose, acetic acid, ethanol, and water (GAEWM) has been widely used for monitoring or trapping G. molesta adults. Previous research has shown that acetic acid captures more moths compared to ethanol; however, the respective roles of acetic acid and ethanol in bisexual attraction remain unknown. This study investigated the olfactory behaviours of virgin females, virgin males, and gravid females to variations in nine concentration levels of acetic acid (A) and ethanol (E) for GAEWM using electroantennography, a wind tunnel experiment, and a field test. There was a significant dose‐dependent response by moths to the GAEWM lure variations that affected the range of lure detection and the probability of a moth being trapped. In contrast, adult sex and mating status had the strongest effect on the behaviours associated with flying close to the trap. For medium level dosages of A and E, one combination with acetic acid exceeding ethanol content (A > E; #3, A:E = 3:1) elicited antennal detection by the test adults, and upwind flight of the females. In another combination with ethanol predominating (E > A; #7, A:E = 1:3), the lured traps caught more males than control groups. For low dosages, with the acetic acid level equal to ethanol (A = E; #1, A:E = 1:1), females flew upwind, and virgin females flew around the lure. For high level dosages, with A > E (#6, A:E = 3:2), the antennae of gravid females and virgin males reacted to the lure. These results concluded that the acetic acid to ethanol ratios of either 3:1 or 1:3 in GAEWM has the potential to improve the attraction of both G. molesta sexes to traps. [ABSTRACT FROM AUTHOR]

The short-lived polygamous moth Grapholita molesta (Busck) is an important fruit pest worldwide. Trapping males by synthetic female sex pheromones is not an effective reproductive control strategy. It is important to improve this technology by understanding the mating system of G. molesta. This study investigated mating opportunities and fertile egg production by altering the operational sex ratio, mating age, and male mating history in repeated single mating and multiple mating in the two sexes. Our results showed that the mating and reproductive parameters of virgin males were affected by the number and age of virgin females. Males preferred a female number ≤three-fifths of the male number or ≤2-day-old females, while they discriminated against a female number ≥three times of the male number or ≥5-day-old females. On the other hand, the mating and reproductive parameters of virgin females were affected by repeated single mating and especially multiple mating under different male mating histories. Females preferred once-mated males and discriminated against virgin males. These results indicated that mating systems including more and older virgin females for virgin males and different virgin males for virgin females may be suitable for suppressing G. molesta populations. Hence, these results revealed that preventing mating of virgin adults by synthetic female sex pheromones should be most effective in controlling G. molesta. [ABSTRACT FROM AUTHOR]

For oligophagous insects, larval performance is very important to evaluate host suitability in host use. However, key indices among all performance traits including survival, development, and fecundity of the adult insect to predict host suitability are not clear. To investigate the key performance indices, we observed the performance of an oligophagous moth Grapholita molesta (Busck) (Lepidoptera: Tortricidae), a pest mainly damaging rosaceous plants, on three apple varieties, three peach varieties, and three pear varieties in the laboratory by placing its eggs on fruits. The moth's fitness was evaluated by the intrinsic rate of increase at fruit variety- and species-level variability. Our results showed that the preovipositional period of female moths and longevity of male moths were the indices primarily predicting intrinsic rates of increase for fruit variety and for fruit species. However, the preovipositional period of female moths was different at species-level variability but not at variety-level variability, whereas the longevity of male moths was not different at variety- or species-level variability. These results revealed that preovipositional period of female moths was a key predictor for host suitability in G. molesta. This study highlighted that gravid females may be a principal indicator in host resource optimization for oligophagous insects. [ABSTRACT FROM AUTHOR]

Abstract Oriental fruit moth (OFM) is a cosmopolitan borer pest. Adults migrate among peach, pear or apple orchards. However, the association of female oviposition with larval fitness over seasonal variation of fruit species have not been reported. This study investigated female oviposition and larval fitness during four sampling months of peach, apple and pear related with maturity. Infested fruits were investigated in three orchards. These results showed that females laid fewer eggs on apple than peach or pear in June and July, but not May and August. Fitness index of larvae on pear was lower than peach or apple in May, June and August, except for July. In June, larvae failed completely to bore into pear. The ranking of infestation ratio was peach orchard (from June to July) > pear orchard (July onward) > apple orchard (late June onward). Based on the above results, peach (June and July) and pear (July and August) were more suitable than apple (June, July and August), whereas peach (May), apple (May) and pear (May and June) were unsuitable for OFM. [ABSTRACT FROM AUTHOR]