谈杨干象鼻虫的检疫及防治

杨干象鼻虫是杨树的主要害虫,为害严重。了解其生长习性,利用高效低毒的绿色威雷药剂进行防治,十分有效,同时还应落实好检疫措施。     

油橄榄象鼻虫生物学特性及其防治

<正> 油橄榄象鼻虫属鞘翅目(Coleoptera Curculionidae)象甲科、象鼻虫属,是油橄榄主要蛀干害虫。我县自七十年代引种栽植油橄榄以来,生长开花结果良好,面积逐步扩大,但油橄榄象鼻虫在我县油橄榄栽植区也大面积发生。为了控制其危害,1987年以来,我们在安阳镇油橄榄栽植区对油橄榄象鼻虫生物学特性进行了观察,并开展综合防治试验,现将结果整理如下。     

栗实象鼻虫的发生及综合防治技术

栗实象鼻虫是危害板栗果实最严重的害虫之一。2a完成1代,以成虫和幼虫危害叶果,被害栗实失去食用价值或发芽能力,并引起发霉腐烂。防治上遵循“预防为主,综合防治”的方针,优先选用农业和生态调控措施,采用消灭幼虫,热水浸种,选用抗虫品种、熏蒸和低毒化学农药防治。     

白纹象鼻虫的发生与防治

椿树苗木具有耐旱、耐寒、耐瘠薄、美观等优点 ,是道路、荒山绿化优良树种。但椿树白纹象鼻虫严重影响着该苗木的生长及生产规模的进一步扩大。1　危害特点经近两年对我县白纹象鼻虫进行调查 ,各虫态中以幼虫危害最重 ,成虫次之。幼虫危害期主要在冬、春季。由于近两年冬暖 ,幼虫冬季仍继续危害 ,取食椿树根部 ,将根部皮层啃破 ,蛀食到木质部 ,严重者将整个树根咬成锯末状 ,根部不能吸收和输送营养 ,地上部枝干因得不到营养而死亡。而其成虫、若虫则取食叶片 ,将叶片咬成缺刻或孔洞。2　生活规律白纹象鼻虫属鞘翅目 ,象鼻虫科 ,在我县一年发…     

栗实象鼻虫无公害防治药剂筛选实验

药剂筛选实验结果表明:无公害农药对栗实象鼻虫的防治作用因药剂种类及施药浓度不同而异。其中,用齐螨素、吡虫啉等5倍液,树干打孔注药效果最佳。     

油橄榄象鼻虫的初步研究

本文对油橄榄象鼻虫的危害情况和象鼻虫形态特征以及生物学特性等作了调查研究,并采用混交林营造措施和化学方法进行防治,用1:800倍液的1605乳剂或50％的敌敌畏乳剂注射堵孔防治幼虫效果很好,人工捕捉成虫效果也好。     

Feeding barriers to reduce damage by pine weevil (Hylobius abietis)

The effectiveness of feeding barriers to protect seedlings against damage caused by pine weevil (Hylobius abietis) was evaluated in experiments established from 1995 to 1999 in southern Sweden. For this purpose the damage done to containerized seedlings protected by various types of barrier was evaluated, and compared with damage to untreated and insecticide (permethrin)-treated seedlings. Three types of feeding barrier that gave significant protection during the first 3 yrs were recognized: coating on the stem bark, shields with a collar at the top, and shields without a collar. The mean accumulated mortality caused by pine weevil for coatings (47%) and shields without a collar (59%) was significantly higher than the corresponding figure for permethrin treatment (13%), whereas shields with a collar (26%) did not differ significantly from the permethrin treatment in this respect. The highest mortality was found for untreated controls (87%).     

Effects of planting time on pine weevil (Hylobius abietis) damage to Norway spruce seedlings

Feeding by pine weevil (Hylobius abietis L.) causes severe damage to newly planted conifer seedlings in most parts of Scandinavia. We investigated the effect of planting time and insecticide treatment on pine weevil damage and seedling growth. The main objective was to study if planting in early autumn on fresh clear-cuts would promote seedling establishment and reduce the amount of damage caused by pine weevil the following season. The experiment was conducted in southern Sweden and in south-eastern Norway with an identical experimental design at three sites in each country. On each site, Norway spruce seedlings with or without insecticide treatment were planted at four different planting times: August, September, November and May the following year. In Sweden, the proportion of untreated seedlings that were killed by pine weevils was reduced when seedlings were planted at the earliest time (August/September) compared to late planting in November, or May the following year. This pattern was not found in Norway. The average length of leading shoot, diameter growth and biomass were clearly benefited by planting in August in both countries. Insecticide treatment decreased the number of seedlings killed or severely damaged in both Norway and Sweden.     

STUDY ON THE FORECAST OF PINE-CONE WEEVIL

INTRODUrnoNScotSpine(Pihussyhasthevar.mongo-lica)jsafme'speiesagainstcol4twand'Poortoilcondihon,whichisoneofthemainplantingsPeciesinnorth-eastregionofChinaandthebe-North"proteChonforest.ThenatUralSctsPinestandsgrowingonthesand-landinHonghuaehiaremanagedastheparent-standforthebaseofseedresource.Butthequalityofpine-conewasseriouslydamagedbythepine-coneweevil..ManyyearssurveyshowedthattheloserateofconewasbetWeen3o%and5o%,evenupto68%inseriouslydamagedyears.Thereductionof1oneyieldinfluenced…     

Histological response of resistant and susceptible white spruce to simulated white pine weevil damage

The traumatic wound response of families of white spruce, Picea glauca (Moench) Voss, resistant or susceptible to the white pine weevil, Pissodes strobi (Peck), were compared after simulated weevil damage. Leaders from 331 trees were wounded just below the apical bud in the spring, coinciding with the natural time of weevil oviposition. A portable 1-mm diameter drill was used to drill 24 holes per leader. Leaders were removed in the fall and examined for evidence of traumatic resin canal formation. Drilled trees had a traumatic wound response 8 times greater than that of undrilled trees; however, undrilled trees also formed some resin canals in response to unknown causes. In the drilled trees, the traumatic wound response extended into the lower part of the leader, where it could possibly affect older larvae. Trees from resistant families responded with greater intensity than trees from susceptible families, by producing multiple rings of traumatic resin canals. Trees from resistant families also responded more rapidly than trees from susceptible families based on number of cells to the first ring of traumatic resin canals. Trees from some resistant families exhibited no traumatic resin canal formation, showing considerable within-family variation and suggesting that other resistance mechanisms might be important. In the year after drilling, there was a reduction in tree diameter growth and trees suffered a reduction in constitutive resin canals in the bark, which suggests some energetic cost of traumatic resin production. There was no indication that the extent of constitutive defenses, as measured by density of cortical resin canals before wounding, was related to the ability to produce traumatic resin canals. Screening trees based on their capacity to produce traumatic resin canals may be useful in selecting genotypes resistant to white pine weevil.     

Replanting conifer seedlings after pine weevil emigration in spring decreases feeding damage and seedling mortality

Replanting at appropriate times after harvesting a coniferous forest stand can help efforts to suppress seedling mortality caused by the pine weevil Hylobius abietis, but optimal times are uncertain. We hypothesized that planting in June rather than May in the third season after harvest would reduce feeding damage by the pine weevil and increase seedling survival rates in central Sweden, where new-generation weevils mainly fly away from their development sites in May/early June. An experimental test of the hypothesis in eight clear-cuts confirmed that planting in June instead of May reduced proportions of seedlings attacked by pine weevil, bark removal from seedlings’ stems, and proportions of seedlings killed by feeding damage. These differences between seedlings planted in May and June declined to some extent with time but still remained significant after two growing seasons. The total seedling mortality after two seasons did, however, not differ significantly between seedlings planted in May and June. Overall, 29% of all seedlings were killed by pine weevil, 4.0% by Hylastes bark beetles, and 2.3% by drought. The results indicate that replanting in spring during the third season after harvest can advantageously continue until mid-June with respect to damage and mortality.     

Pine weevil (Hylobius abietis) damage to cuttings and seedlings of Norway spruce

Damage caused by pine weevil (Hylobius abietus L.) to planted seedlings and cuttings of Norway spruce (Picea abies (L.) Karst.) was studied at five clearcut sites in south-eastern Sweden. The main objective was to compare the two types of stock in terms of attack frequency and mortality due to pine weevil feeding. Cuttings and seedlings with the same initial stem-base diameter (4 mm) were compared. Two sites were harvested and scarified shortly before planting, two were harvested shortly before planting, but were not scarified, and one was harvested 2 years before and scarified the autumn before planting. The total mortality 5 years after planting was highest, greater than 90%, at the new, non-scarified sites, and lowest, 23%, at the old, scarified site. More than 90% of the mortality was caused by pine weevil feeding. Attack frequency and pine weevil induced mortality were significantly higher among seedlings than among cuttings. Mortality due to pine weevil damage was 4–43% higher in seedlings than in cuttings after the fifth year. Of the cuttings and seedlings that were attacked in the first year, a significantly higher frequency of the seedlings were girdled. The higher resistance of cuttings to pine weevil damage may partly explain the more rapid growth of cuttings reported in other studies. However, the causes of their higher resistance need to be further investigated. The thicker bark and needles on the stem base of the cuttings could be important in this respect.     

Stockings for protection of containerized conifer seedlings against pine weevil (Hylobius abietis L.) damage

The effectiveness of a stocking, constructed of nylon and cotton netting, in protecting containerized conifer seedlings against pine weevil attack was evaluated in field tests on 37 clear‐cut reforestation areas in southern and central Sweden. The stockings significantly reduced pine weevil feeding on treated seedlings as well as seedling mortality. The protective effect of the stockings was similar to that of an insecticide (permethrin) treatment. In most experiments the survival of stocking‐enclosed seedlings was satisfactory from a practical point of view, whereas untreated control seedlings suffered heavy mortality.     

Strawberry blossom weevil Anthonomus rubi Herbst (Col.: Curculionidae): relationships between bud damage, weevil density, insecticide use, and yield

The activity of overwintered strawberry blossom weevils, Anthonomus rubi Herbst, measured as cut buds and adult weevils, was recorded weekly in sprayed and unsprayed quadrats in young and old strawberry plantings. The study was done in nine ‘Korona’ fields in a district with high A. rubi density, in the southeast of Norway, in 2000. During the period of study, the cumulative number of cut buds and adult weevils found by tapping whole plants above a bowl were highly correlated. An increase in sampled weevils was followed by an increase in cut buds 1–2 weeks later. Thus, sampling adults has potential for predicting the bud damage. In five of the six fields where yield was measured, a negative relationship between cut buds and the saleable yield was found. The effect of spraying was relatively low: A. rubi activity was reduced by 21% and the saleable yield increased by 16%. We conclude that present spraying practices are not very efficient in preventing A. rubi damage in the area studied.     

杨干象化学防治研究

杨干象是我国重要的杨树检疫害虫之一，为杨树速生丰产林危险性的蛀干害虫。以前有关资料对该虫的防治技术有一定的记载，但仍不能满足有效防治的需要。作通过11种药剂的防治试验，进行了药剂种类与浓度的筛选，结果看出，采用50％甲胺磷乳油30－80倍液涂干或喷干，均可收到理想的防治效果。以该药剂30倍液对1年生杨树幼树涂干防治，成本约为37．5元／hm^2 ,以80倍液对2年生幼树人工喷雾防治，成本约为60元/hm^2，对3年生幼树进行机械喷雾防治，成本约为90元／hm^2；采用氧化乐果进行防治也可收到较好的防效。