Ruiyan Ma

Research on the practical parameters of sex pheromone traps for the oriental fruit moth.

BACKGROUND The oriental fruit moth (OFM) is a worldwide fruit-boring insect pest. In China, OFM monitoring traps use a sex pheromone lure, but their overall design is varied. As such, there is a critical need to develop a standardised OFM trap design. In this field study, ten different trap shapes in varying combinations of colours and sizes (such as trap length and surface area) were examined. RESULTS The results showed that there was no significant difference in the trapping efficiency between eight colours. The ship-shaped trap could kill more OFM in a short period, whereas the automatic watering basin trap could be more effective in the long run. The optimal trapping diameter of the basin trap was 25 cm. The trapping efficiency of triangle traps with diameters of less than 10 cm was better than that of triangle traps with diameters of over 30 cm. The trapping number of pasteboard traps obviously declined when the surface area increased, and the pasteboard trap with a single board possessed excellent trapping efficiency. CONCLUSION The results provide useful information for the design of standardised sex pheromone traps for monitoring as well as trapping of OFM in the field.

Transcriptome Analysis and Identification of Major Detoxification Gene Families and Insecticide Targets in Grapholita Molesta (Busck) (Lepidoptera: Tortricidae)

The oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), is an important pest of most stone and pome fruits and causes serious damage to the fruit industry worldwide. This insect pest has been primarily controlled through the application of insecticides; as a result, G. molesta has developed resistance to many different types of insecticides. To identify detoxification genes, we have, de novo, sequenced the transcriptome of G. molesta (Lepidoptera: Tortricidae) and yielded 58,970 unigenes of which 26,985 unigenes matched to known proteins. In total, 2,040 simple sequence repeats have been identified. The comprehensive transcriptome data set has permitted us to identify members of important gene families related to detoxification in G. molesta, including 77 unigenes of putative cytochrome P450s, 28 of glutathione S-transferases, 46 of Carboxylesterases, and 31 of insecticide targets. Orthologs of some of these unigenes have shown to play a pivotal role in insecticide resistance in other insect species and those unigenes likely have similar functions in G. molesta.

Increased trapping efficiency for the peach fruit moth Carposina sasakii (Matsumura) with synthetic sex pheromone

Carposina sasakii Matsumura is one of the most serious fruit‐damaging pests in Southern East Asia. The management of C. sasakii using sex pheromones has proven to be simple, effective and environmentally friendly with respect to monitoring and controlling this pest. To apply sex pheromone‐based pest control techniques effectively, we characterized a range of application parameters, as well as the effects of synthetic sex pheromones, in jujube orchards. Trapping radius was determined by comparing the mean number of trapped individuals at different inter‐trap distances, and mating disruption parameters were inferred by comparing the rate of trapping efficiency reduction and the infestation ratio of fruits in the experimental fields by uniformly placing different number/types of lures/100 m2. These studies revealed capture rates with significant differences across 10–50‐m inter‐trap distances: for example, a 30‐m or greater inter‐trap distance was suitable for monitoring and mass trapping, whereas distances <20 m significantly decreased the trapping efficiency in the testing area. The studies lay the foundation for the implementation of these technologies within the context of a well‐conceived control strategy against this significant agricultural pest.

Wing shape variation among three biotypes of Myzus persicae (Sulzer, 1776) (Hemiptera: Aphididae)

Abstract. The green peach aphid, Myzus persicae (Sulzer, 1776) can cause significant economic losses in different crops in China. In the present study, we evaluated wing shape and size variation among biotypes from tobacco, Nicotiana spp. (Solanaceae), cabbage, Brassica oleracea L. (Brassicaceae), and peach, Prunus persica (L.) Batsch (Rosaceae), and tested whether specimens could be distinguished at the population level. Fifteen landmarks were measured on the wings and used to generate geometric morphometric size and shape data from 137 specimens of M. persicae from three host plants: tobacco, cabbage and peach. Analysis of wing size showed that the peach biotype had the smallest wing centroid size. A one-way ANOVA of centroid size showed significant inter- and intra-populational differences. A Tukey post-hoc test revealed that the wing centroid size of the peach population was significantly smaller than that of either the tobacco or cabbage population. DFA cross-validation test showed that all tobacco biotype specimens were correctly classified, while 83% and 84.1% of peach and cabbage biotype specimens, respectively, were correctly classified. These results suggest that geometric morphometrics based on wing shape has potential for distinguishing M. persicae biotypes.

Potential application of digital image-processing method and fitted logistic model to the control of oriental fruit moths (Grapholita molesta Busck).

Monitoring of oriental fruit moths (Grapholita molesta Busck) is a prerequisite for its control. This study introduced a digital image-processing method and logistic model for the control of oriental fruit moths. First, five triangular sex pheromone traps were installed separately within each area of 667 m2 in a peach orchard to monitor oriental fruit moths consecutively for 3 years. Next, full view images of oriental fruit moths were collected via a digital camera and then subjected to graying, separation and morphological analysis for automatic counting using MATLAB software. Afterwards, the results of automatic counting were used for fitting a logistic model to forecast the control threshold and key control period. There was a high consistency between automatic counting and manual counting (0.99, P < 0.05). According to the logistic model, oriental fruit moths had four occurrence peaks during a year, with a time-lag of 15-18 days between adult occurrence peak and the larval damage peak. Additionally, the key control period was from 28 June to 3 July each year, when the wormy fruit rate reached up to 5% and the trapping volume was approximately 10.2 per day per trap. Additionally, the key control period for the overwintering generation was 25 April. This study provides an automatic counting method and fitted logistic model with a great potential for application to the control of oriental fruit moths.

Three physical barriers with obvious effects on Carposina sasakii selection behavior to two dominant jujube tree volatiles

The peach fruit moth (PFM), Carposina sasakii Matsumura (Lepidoptera: Carposinidae), a severe pest of Ziziphus jujuba Miller fruit trees (jujube, Rhamnaceae) mainly grown in China, has increasingly hindered the development of the jujube industry in recent years. In order to provide a theoretical basis for a physical obstruction method, we evaluated the effect of three commonly sold physical barriers on PFM host‐searching behavior. Two principal volatiles generated by the jujube tree, α‐farnesene and cis‐3‐hexenyl acetate (leaf acetate), were used as references to detect electroantennography (EAG) response values of 2‐, 4‐, and 6‐day‐old PFM adults. The results indicated different EAG responses toward α‐farnesene and leaf acetate between different ages of PFM, and males responded differently than females. The EAG responses were stronger in 4‐day‐old males to leaf acetate and in 2‐day‐old females to α‐farnesene. The two‐choice behavioral Y‐tube olfactometer assay confirmed that PFM was strongly attracted to α‐farnesene and leaf acetate. We determined the EAG and behavioral responses of PFM after spraying three kinds of physical barriers: Liquid Film Fruit Bag, High Lipid Film, and Jujube Protection No. 1. We obtained strong inhibitory effects on PFM attraction to both volatile lures using these barriers, including negative taxis by both females and males to Liquid Film Fruit Bag and Jujube Protection No. 1. We can infer that Liquid Film Fruit Bag is the most promising potential physical barrier for PFM control, with Jujube Protection No. 1 ranking as second‐best.

Methods to measure performance of Grapholitha molesta on apples of five varieties

Host plants will affect the performance and population dynamics of the polyphagous insect pest Grapholitha molesta (Busck) (Lepidoptera: Tortricidae). Cultivar‐level variability needs to be considered in assessing the performance of G. molesta. We evaluated the fitness of G. molesta on five apple varieties in the laboratory by placing eggs on apples and observing their performance including survival, development, and fecundity of the adult insect. Our results demonstrated differences between indices such as larval duration, pupal weight, egg production, length of tunnel, and exiting rate of larvae, which gave similar host rankings. Variety Danxia was less suitable than Jinqing and Shuohong, and more suitable than Empire and Jinxing. However, other indices such as pupal duration, total pre‐oviposition time, and the estimated population parameters resulted in a different host ranking. We calculated weighted fitness scores to overcome the problem of inconsistent rankings. Empire changed from being the second highest ranking variety based on all population parameters to the second lowest using weighted fitness scores. The difference in ranking observed between apple varieties demonstrates the care needed in predicting population performance in the field using single traits.