Effects of Leptocybe invasa Damage on Chemical Components of Eucalyptus

[Objective] The aim was to illustrate the relation between Leptocybe invasa and eucalyptus, so as to provide the basis for scientific control of L. invasa. [Method] The chemical components of eucalyptus were extracted by solid phase micro-extraction （SPME） technique and ethanol extraction method, and detected by gas chromatograph-mass spectrometer. The relative contents of various components were determined by area normalization. [Result] When eucalyptus was damaged by L. invasa, not only some substances disappeared, but also new substances were induced. Among 4 induced volatiles, the content of terpinolene was the highest of 37.66%. Eight new chemical substances were also detected from the ethanol extract of damaged leaves, and the content of 3-phenyl-2-propenyl phenpropionate was the highest of 30.95%.[Conclusion] The damage caused by L. invasa had obvious effect on composition and contents of chemical components of eucalyptus.

Screening of 19 genotypes of Eucalyptus spp.against gall wasp(Leptocybe invasa) in North-western India

The present study was carried out at Punjab Agricultural University,Ludhiana,India.Nineteen clones of Eucalyptus spp.were evaluated for tolerance to gall wasp.The total number of galls per plant were recorded at 1 month after planting（MAP） and the number of galls per branch were recorded at 4 and 7 MAP.Gall wasp incidence（number of galls） was recorded on a whole plant basis during the seedling stage and the number of galls were recorded from the upper,middle and lower crown places at 4 and 7 MAP.Categorization was done on the basis of relative gall-wasp damage by keeping in view the total number of galls per plant and branch（leaves and petiole）.No clone was found free from gall damage.Clones C-526,P-23 and P-103 were the least attacked by the gall wasp.Incidence as indicated by number of galls caused by Leptocybe invasa on eucalypts was higher in March than in December.

The Abundance and Population Dynamics of Leptocybe invasa (Hymenoptera:Eulophidae) Galls on Eucalyptus spp.in China

The blue gum chalcid, Leptocybe invasa Fisher ＆ La Salle, invaded China in 2007 and has subsequently caused substantial damage to eucalyptus trees. In the current paper, we investigated the susceptibility of 10 Eucalyptus spp. and Eucahetus dunnii to L. invasa in the field, determined the density of galls as well as the gall volume on these tree species, and monitored the population dynamics of wasps in Hainan and Guangdong provinces of China. The order of susceptibility to L. invasa was Eucalyptus urophyllaxEucalyptus camaldulensis〉E, urophylla （coppices）〉Eucalyptus exserta〉 Eucalyptus grandisxE, urophylla in Hainan, and Eucalyptus propinqua〉Eucalyptus saligna〉E, exserta〉Eucalyptus microcorys〉Eucahetus dunnii〉E, camaldulensis〉Eucalyptus tereticornis〉Eucalyptus robust in Guangdong, China. Although L. invasa generally damages the midribs and petioles of young leaves and the tender bark of twigs of eucalyptus, galls were not observed on leaves of E. microcorys, E. camaldulensis, or E. dunnii. Gall volume significantly differed among the tree species, and gall volume and wasp number were positively correlated. In Dongfang, Hainan Province, the overwintering period of L. invasa emergencing through the year was from the end of December to March of the next year, and the number of population was the greatest on E. urophylla^E, camaldulensis, and the smallest on E. grandis E. urophylla. In Guangzhou, Guangdong Province, L. invasa hardly emerged in winter from December to June of the next year, and the population was the greatest on E. propinqua, and the smallest on E. microcorys.

Effects of Different Eucalyptus Varieties(Clones) on Fitness and Development of Leptocybe invasa Fisher et La Salle

The damage status of L. invasa on different Eucalyptus varieties( clones) were surveyed in the field,and effects of Eucalyptus varieties on fitness,development and reproduction of this pest were studied in the study. Results showed that:( 1) Most of the major Eucalyptus varieties( clones) could be attacked by L. invasa in Fujian Province,and galls formed on E. urophylla × E. camaldulensis DH201-2,E. gradis QG3,E. dunnii,E. urophylla cU6,E. grandis × E. urophylla GL9,E. robusta and E. exserta; L. invasa could develop and complete its life cycle on above varieties.( 2) The damage degree of different Eucalyptus varieties( clones) was different from fitness degree to L. invasa. L. invasa had different selection frequency,fecundity and number of larvae per gall on different Eucalyptus varieties( clones).( 3) In addition to little difference in female ratios,L. invasa feeding different Eucalyptus varieties( clones) had extremely significant differences in the indicators such as number of emerged L. invasa,body mass of female adult,fecundity,longevity,etc.( 4) According to the fitness index( FI),the host plants of L. invasa were divided into 4 types by cluster analysis: suitable host,moderately suitable host,less suitable host and unsuitable host; the fecundity of each female was more than 70 eggs in suitable host,which was adequate to lead to potential population outbreak of the pest. Host fitness index could be used as a comprehensive evaluation index for screening of resistant varieties( clones) in production.