Possible functions of the microtrichia on the cuticle of Ulomoides dermestoides(Chevrolat)(Coleoptera:Tenebrionidae)

Ulomoides dermestoides （Chevrolat） （Coleop- tera： Tenebrionidae） is one of the most notorious pests in northeastern China. We examined microtrichia on the thorax, elytra and abdomen of U. dermestoides using scanning electron microscopy and recorded their confor- mations （size, shape and insertion method） and distribu- tions （length, width and location）. Possible functions of the microtrichia were （1） stridulation： microtrichia on the inner surface of the elytra interacted with microtrichia on the dorsoventral axis of the thorax or on the costal vein of the hind wing; （2） to increase friction： at the major surface on the middle of the abdominal tergum, hind-wings, inner surface of the medial edge of the elytra and the posterior end of the elytra; （3） protection： the microtrichia covering the posterior face of the abdomen conserved water in the body and protected the body from damage; and （4） sensing organ： the special shape of the microtrichia on the nerva- tion near the vannal fold of the hind wing, the anterio- metapleuron on the metathorax, and the posterior field of the abdomen could perceive the environment. In conclusion, the size and shape of the microtrichia are tightly related to their functions, which may have evolved with the beetles＇ lifestyle.

A study on JA-and BTH-induced resistance of Rosa rugosa‘Plena’to powdery mildew(Sphaerotheca pannosa)

Different concentrations of jasmonic acid(JA)and benzothiadiazole(BTH) were sprayed on 2-year-old Rosa rugosa‘Plena’ seedlings. The induced resistance of JA and BTH to Sphaerotheca pannosa(Wallr.) and the changes of their related physiological indices were investigated. Results showed that JA and BTH treatments had inhibitory impacts on S. pannosa infection. The optimal concentration of JA and BTH was 0.5 mmol/L for the disease-resistance induction of the leaves, its inductive effect was up to 66.36% for BTH and 54.49% for JA. Our results confirmed that exogenous JA and BTH significantly improved R. rugose ‘Plena’ resistance to S. pannosa. When treated with JA and BTH, activities of the three defense enzymes(POD, PPO, and PAL) increased significantly.Contents of total phenolics, flavonoids, and lignin also increased significantly. It is inferred from these results that exogenous JA and BTH could improve the resistance of R.rugose ‘Plena’ to S. pannosa through enhancing activities of the defensive enzymes and accumulation of secondary metabolites in the leaves.

Effect of jasmonate treatments on leaves of Rosa rugosa‘Plena’and detoxification enzymes and feeding of adult Monolepta hieroglyphica

To study the effect of jasmonates(JAs)on the resistance of economic forest plants to insects,R osa rugosa‘Plena'leaves were treated with 1 mmol/L jasmonic acid(JA),methyl jasmonate(MeJA)and Z-jasmone,then the content of tannin and total phenol in leaves and the feeding area of Monolepta hieroglyphica adults on leaves were measured.Changes in the activities of detoxification enzymes in adult M.hieroglyphica that had fed on leaves treated with JAs were also studied.Tannin and total phenol levels in leaves increased significantly after treatment with JAs,and tannin level was 1.36–1.55-fold higher than in the control after treatment with 1 mmol/L MeJA.The total content of phenol in leaves treated with 1.0 mmol/L Z-jasmone increased by 1.33–2.20-fold compared with those of the control.The activities of detoxification enzymes in adults were inhibited to differing degrees:activity of alkaline phosphatase(AKP)first increased,then decreased;the activities of acid phosphatase(ACP),glutathione S-transferases(GSTs)and carboxylesterase(CarE)following treatment with 1 mmol/L MeJA were significantly reduced and were 22%–31%,11%–26%,and 11%–31%lower than those of the control,respectively.Moreover,the feeding area of adult M.hieroglyphica on the leaves treated with JAs was significantly reduced(P<0.05).The feeding area of economic forest R.rugosa‘Plena'leaves treated with 1 mmol/L MeJA decreased by 17%–43%compared with that of the control.Moreover,the decrease in the adult M.hieroglyphica feeding area was highly positively correlated with the content of tannin and positively correlated with the contents of total phenol of economic forest R.rugosa‘Plena'leaves.The reduced feeding area of adult M.hieroglyphica was highly negatively correlated with the activities of AKP and ACP and negatively correlated with those of the GSTs.In conclusion,the use of 1 mmol/L MeJA can noticeably decrease the deleterious effects of adult M.hieroglyphica.

Effectiveness of entomopathogenic fungal strains against poplar/willow weevil(Cryptorhynchus lapathi L.)larvae

The poplar and willow weevil,Crypto rhynchus lapathi L.,a major universally destructive wood-boring insect has become one of the important quarantine pests that is extremely destructive to forestry development and needs to be controlled.Entomopathogenic fungi(EPF) are considered safe and friendly for humans and the environment and play important roles in controlling insect pest populations.In this study,the screening of entomopathogenic fungi for control of C.lapathi is reported through the evaluation of virulence of four fungal Beauveria bassiana(CFCC81428,CFCC83116,CFCC83486,CFCC87297)strains,one B.brongniartii(CFCC83487) strain and one Metarhizium anisopliae(CFCC88953) strain.The virulence of the different strains was appraised by correct mortality rate,cumulative mortality rate,median lethal concentration(LC_(50)) and median lethal time(LT_(50)).B.bassiana strains CFCC81428 and CFCC83116 were the most virulent among the six strains with a mortality up to 100%,and the LT_(50) were 2.7 and 3.1 days.Five conidia concentrations of three strains(CFCC81428,CFCC83116 and CFCC87298) that caused high virulence was screened for dose-relationship.Their effect on controlling C.lapathi larvae were also determined under field condition by brushing conidia suspensions on C.lapathi larvae infested in a poplar trunk.The cumulative rate in the field was lower than those obtained from the laboratory,but the order of the virulence of different strains did not change.Mortality in all three strains occurred at their highest concentration(1.0 × 10^(8) conidia mL^(-1)).Under field conditions,the CFCC81428 strain was the most effective,causing mortalities of 80.3% and 75.2%in two plots in Beipiao and Lindian counties,respectively,followed by CFCC83116(69.1%,66.6%) and CFCC87298(60.7%,59.3%).Based on our results,the B.bassiana strain CFCC81428 has the potential as a biological insecticide to control C.lapathi larvae.