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Eucommia ulmoidesis a small tree that has evolved strong pest resistance. This study investigated the mechanism of this resistance by evaluating pest damage and antifeedant activity of the secondary metabolite gutta-percha. In the field,E. ulmoidesdisplayed an average plant resistance of 93.3%, with most damage confined to leaves. We assessed the effects of gutta-percha as a feeding deterrent againstHyphantria cuneaandAnoplophora glabripennislarvae by mixing it into or daubing it onto the surface of artificial diets. Diets containing more than 6% gutta-percha significantly reduced the amount of feeding byA. glabripennislarvae and the body length ofH. cunealarvae. In addition, approximately 95% of the artificial diet was not consumed compared to the control without gutta-percha. The content, distribution, properties, and dynamics of gutta-percha inE. ulmoidesindicate that gutta-percha may function as a physical-chemical barrier against insect pests. [ABSTRACT FROM AUTHOR]

Chlorophorus caragana(Coleoptera: Cerambycidae) is a trunk borer that feeds onCaraganashrubs in the desert. There are five species ofCaraganaplant in the distribution area ofCh. caragana. We investigated damagedCaraganaplants in the field. Olfactory responses of femaleCh. caraganato plants and identified volatile compounds fromCaraganaplants were further evaluated.Caragana davazamciiwas severely damaged in the field, followed byCaragana microphylla. No damage was found to the other three species. Behavioral experiments showed thatC. davazamcii, C. microphylla, andCaragana korshinskiiwere attractive to female insects.Caragana ordosicacould repel and avoid female insects.Caragana brachypodahad no effect on the orientation behavior of female insects. Seventy volatile components were identified from theCaraganaplants, and (Z)-β-ocimene, 1,3-pentadiene, (Z)-3-hexenyl acetate, perillene, chrysanthenone, and limonene were the most abundant volatiles identified from theCaraganaplants. The volatiles were categorized into three groups. Those most attractive toCh. caraganaconsisted of chrysanthenone, 1,3-pentadiene, and (Z)-β-ocimene. Those repellingCh. caraganaconsisted of perillene, dibutyl phthalate, nonanal, and pentadecane, and those irrelevant to each other consisted of (Z)-3-hexenyl acetate, 1-octene, nonene, decanal, (Z)-3-hexenol, and α-pinene. [ABSTRACT FROM AUTHOR]

The amino acid, protein, carbohydrate, and mineral element contents and composition of the xylem, phloem, and leaves of healthy and insect-damaged Caragana korshinskii plants were analyzed to evaluate the changes in the nutrient content of C. korshinskii after damage by Chlorophorus caragana. The amino acid content decreased in the leaf and phloem but increased in the xylem in response to damage, while the protein content did not change in the leaf, increased in the xylem, and decreased in the phloem. The carbohydrate content increased slightly in the leaf but decreased in the xylem and phloem. The six mineral elements analyzed, namely, phosphorous, potassium, magnesium, zinc, manganese, and iron decreased in the xylem, phloem, and leaf. The present results may provide a basis for understanding the mechanisms underlying the effect of C. caragana on the loss of viability of C. korshinskii. [ABSTRACT FROM AUTHOR]