An Annual Dynamic Study On The Damage Of Eucalyptus Leaves In Harbin

Elm tree,Ulmus pumila,as one dominant horticultural tree,is fed by some elm leaf beetle species,such as Ambrostoma quadriimpressum in north China,according researches are still at primary stages.We observed injury dynamics caused by these leaf beetle species during the whole growth season and damage components contributed by different beetle species.Moreover,we analyzed the key environmental factors influencing the damage level on elm leaves by these beetles,and described the over-wintering related biological(morphological and behavioral)features of these insects.We found that,firstly,during the whole growth season,damage level on elm leaves by these beetles increased step by step,and reached the top level before over-wintering;on the other side,injury caused by the Ambrostoma quadriimpressum was the dominant part.Secondary,our studies indicated that “ interval among trees” was the key factor influencing injury level of elm leaves by the beetles,intensive planting of elm trees would lead to serious infestation of these leaf beetles;good soil condition for over-wintering would enhance this kind of damage on elm leaves;injury on bigger elm tree would be more serious;elm tree individual with serious injury often be chosen to take control measures;however,because horticulture workers would select bigger trees to carry out pest management for economic reasons,instead of all the elm trees within specific area,only the not-flying Ambrostoma quadriimpressum could be under control to some extent.Thirdly,biological features research showed that survival rate of female leaf beetle adult was higher;post-over-wintering,before elm leaves emergence,still the rate of female adult was higher;it's induced that the female ones have bigger size,more energy conservation.For behavioral features,fake-death time of female one is longer,and speed is relatively faster.For the male adults,smaller individuals is easier to die during over-wintering,male percentage decreased significantly post-over-wintering.