树干打孔注药防治杨树膜肩网蝽试验

利用40%氧乐果乳油、10%吡虫啉水乳剂、40%毒死蜱乳油、40%杀扑磷乳油对危害杨树的膜肩网蝽进行树干打孔注药防治,试验结果表明,40%氧乐果防效最好,施药3 d后虫口减退率为97.6%,防效达97.58%;10 d虫口减退率99.04%,防效达99.16%,明显优于其他药剂。     

白蜡窄吉丁幼虫药剂防治试验

白蜡窄吉丁是我国重要的检疫性蛀干害虫,对白蜡属多个树种和美国流苏树危害较重。为了防控白蜡窄吉丁幼虫,选择不同药剂组合对绒毛白蜡进行树干喷洒和打孔注药防治。结果表明：树干喷洒7种药剂组合的防效顺序为40%氧乐果>1%甲维盐+25%溴氰菊酯>5%高氯·甲维盐>5%吡虫啉+20%氰戊菊酯>20%氰戊菊酯>1%甲维盐>25%溴氰菊酯;打孔注射8种药剂组合的防效顺序为40%氧乐果+1%有机硅>1%甲维盐>5%吡虫啉+1%有机硅>5%吡虫啉+20%氰戊菊酯+1%有机硅>1%甲维盐+25%溴氰菊酯+1%有机硅>5%高氯·甲维盐+1%有机硅>25%溴氰菊酯>20%氰戊菊酯。树干喷洒时,药剂的合理复配能够提高对白蜡窄吉丁幼虫的林间防效;在打孔注药中,药剂的复配使用并未提高对害虫的防效。在2种施药方法中40%氧乐果都具有最好的防效,而使用打孔注药方式防效更好。     

不同剂型苯氧威防治杨扇舟蛾试验

采用不同剂型苯氧威分别对杨扇舟蛾第2代幼虫进行喷烟和喷雾防治试验,结果表明,3%高渗苯氧威EC和柴油按1:5、1:8喷烟防治防效高峰3～7 d,7 d防效分别为89.9%、76%.3%高渗苯氧威EC 2-000倍、3 000倍喷雾防治7 d防效分别为91%、88.9%.25%苯氧威WP4 000倍、6 000倍、8 000倍喷雾防治防后7 d的防效分别为94%、88.9%、56.4%.     

松沫蝉若虫和成虫林间防治技术研究

松沫蝉是危害多种松树的一种刺吸式害虫,为掌握松沫蝉若虫和成虫的药剂防治技术,通过在林间喷洒和打孔注射不同浓度的药剂防治松沫蝉若虫,飞机喷洒药剂防治松沫蝉成虫。结果显示:林间喷洒5 d后,溴氰菊酯3种浓度防效都在89%以上,溴氰菊酯500倍液的防效最高,为93.6%;吡虫啉3个浓度药剂的防效都在70%~80%,吡虫啉500倍液的防效最高,为78.5%。打孔注药5 d后,氧乐果10倍液、20倍液的防效分别为90.4%和86.9%。飞机喷洒溴氰菊酯24 h内松沫蝉死亡率较高,喷药3 d后,每株死亡数量达到1 234~3 542头,飞防杀虫率90%以上,使松沫蝉得到有效控制。     

避雨栽培条件下西昌市‘克瑞森’葡萄主要虫害物理防控效果

以促进农药减施和提高果实质量为目的,探究避雨栽培条件下6种物理防治措施对西昌市‘克瑞森’葡萄主要虫害的防效。结果表明：在单独实施的6种物理措施中,有5种对夜蛾的防效>40%,以灯光诱杀效果最好;3种对实蝇的防效>62%,以纱网阻隔效果最好;2种对蓟马的防效>43%,以性信息素诱杀效果最好;仅有挂色板1种措施利于粘杀蚜虫,但防效<25%;6种措施对螨类和蚧壳虫的防效<10%。综合实施6种物理措施防控,葡萄虫穗、虫叶、虫果的发生率分别比对照低49.8%、44.35%、49.5%;优等果率比对照高74.64%,中等果率和次果率比对照低36.04%、46.53%;增收3 945元。综合实施物理防控比单独实施的虫叶率、虫果率平均防效高57.14%、50.74%。     

不同药剂对薄壳山核桃警根瘤蚜的防治初报

测定内吸性药剂吡虫啉、乐果和敌敌畏对薄壳山核桃Carya illnoensis k.Koch警根瘤蚜Phylloxera notabilis的防治效果。试验结果表明,3种药剂施用后警根瘤蚜的数量均大幅减少,防效均在91%以上,以6%吡虫啉可湿性粉剂防效最好;施药4个月后,6%吡虫啉可湿性粉剂处理调控效应最好,株危害率和叶片危害率分别降低至3.3%和8.5%。生产上可选用6%吡虫啉可湿性粉剂进行防治。     

三种药剂防治核桃举肢蛾效果研究

为筛选防治核桃举肢蛾效果较好的杀虫剂,本试验选用毒死蜱、乙酰甲胺磷和杀灭菊酯3种杀虫剂对核桃举肢蛾进行试验。试验结果表明,试验选用的3种杀虫剂不同剂量处理对核桃举肢蛾均有一定的防治效果。其中,40%乙酰甲胺磷乳油以1000倍液处理对核桃举肢蛾表现出了最高的防效,为92.11%;48%毒死蜱乳油以1000倍液处理对核桃举肢蛾的防效次之,为85.35%;20%杀灭菊酯乳油以1500倍液处理的防治效果最低,为76.27%。3种试验药剂中40%乙酰甲胺磷乳油和48%毒死蜱乳油以1000倍液处理对核桃举肢蛾的防效较好,可以在生产中推广应用。     

临夏花椒棉蚜无人机药剂防治试验

采用植保无人机施药的方式,进行1.8%阿维菌素乳油、10%啶虫脒乳油、10%吡虫啉可湿性粉剂不同倍液对花椒棉蚜的田间药效试验。结果表明,药后1 d和7 d, 1.8%阿维菌素乳油对花椒棉蚜的防治效果最好,其中100倍的防效最高,分别为85.99%、90.05%, 200倍和300倍的防效次之。10%啶虫脒乳油和1.8%阿维菌素乳油的防效在药后1、7 d均出现显著差异,10%吡虫啉可湿性粉剂的防效在药后1 d和7 d都显著低于以上两种药物。     

不同施药技术对蛀干害虫的防效比较试验

比较了根部施药、钻孔注药、插药瓶、挂药袋以及从虫孔注入药液和药膏等方法对蛀干害虫的防效。挂药袋仅对孵化初期的臭椿沟眶象防效较好，从虫孔注入药液对向下或上下串食的害虫防效较好，SGY药膏对向各种方向蛀食的害虫防效均高于90．0％，其他方法防效较差。     

虫孔注射农药防治黑杨光肩星天牛大龄幼虫试验

在浙江省武义县后陈等地黑杨林内采用不同浓度的７种农药对黑杨光肩星天牛大龄幼虫进行虫孔注射防治试验，结果显示，选用内吸性农药４０％ 氧乐果乳油和５０％ 甲胺磷乳油进行防治效果好，用药量每虫孔４ ｍ Ｌ，防治效果９０％ ～１００％     

园林工程移植大树的生长状况调查与分析

长春市不同绿地移植大树的生长状况调查结果表明：调查绿地移植的大树（平均胸径16．5～26．0cm）平均成活与趋向成活率只有60．8％,死亡和趋向死亡率却高达39．2％。2013年春季栽植的樟子松大树,平均胸径为11．8em的大树,死亡率为48．6％,而平均胸径为7．5cm的树木,死亡率只有3．5％。移植体量小的植株容易成活。     

桉树红叶枯梢病防治试验初报

桉树红叶枯梢病可施用硼、铜、锌等微量元素进行有效防治。设计了6种处理。其中,硼砂10 g+硫酸铜5 g组合对树高生长促进作用较大;硼砂10 g+硫酸铜5 g+硫酸锌5 g组合对减少丛枝以及减少红叶率效果较明显。春季施放效果好于秋冬季。春季施用20 d后就见效,50 d后病状基本消失,树体基本恢复健康。     

Root and transpiration studies on young Norway spruce trees with die back symptoms in Sweden

In the spring of 1977, scattered trees in young plantations of Norway spruce showed discoloration and loss of 1976 needles on twigs just below the apex. The main roots of damaged trees were smaller than those of healthy trees, and the extension roots lacked short roots and mycorrhizae. The transpiration rate of the current shoots of damaged trees was also higher. The damage was assumed to be the result of drought during the two previous years; the trees were thought to differ genetically in their ability to withstand water stress.     

Soil temperature and plant growth stage influence nitrogen uptake and amino acid concentration of apple during early spring growth

In spring, nitrogen (N) uptake by apple roots begins about 3 weeks after bud break. We used 1-year-old 'Fuji' Malus domestica Borkh on M26 bare-root apple trees to determine whether the onset of N uptake in spring is dependent solely on the growth stage of the plant or is a function of soil temperature. Five times during early season growth, N uptake and total amino acid concentration were measured in trees growing at aboveground day/night temperatures of 23/15 degrees C and belowground temperatures of 8, 12, 16 or 20 degrees C. We used (15NH4)(15NO3) to measure total N uptake and rate of uptake and found that both were significantly influenced by both soil temperature and plant growth stage. Rate of uptake of 15N increased with increasing soil temperature and changed with plant growth stage. Before bud break, 15N was not detected in trees growing in the 8 degrees C soil treatment, whereas 15N uptake increased with increasing soil temperatures between 12 and 20 degrees C. Ten days after bud break, 15N was still not detected in trees growing in the 8 degrees C soil treatment, although total 15N uptake and uptake rate continued to increase with increasing soil temperatures between 12 and 20 degrees C. Twenty-one days after bud break, trees in all temperature treatments were able to acquire 15N from the soil, although the amount of uptake increased with increasing soil temperature. Distribution of 15N in trees changed as plants grew. Most of the 15N absorbed by trees before bud break (approximately 5% of 15N supplied per tree) remained in the roots. Forty-six days after bud break, approximately one-third of the 15N absorbed by the trees in the 12-20 degrees C soil temperature treatments remained in the roots, whereas the shank, stem and new growth contained about two-thirds of the 15N taken up by the roots. Total amino acid concentration and distribution of amino acids in trees changed with plant growth stage, but only the amino acid concentration in new growth and roots was affected by soil temperature. We conclude that a combination of low soil temperature and plant developmental stage influences the ability of apple trees to take up and use N from the soil in the spring. Thus, early fertilizer application in the spring when soil temperatures are low or when the aboveground portion of the tree is not actively growing may be ineffective in promoting N uptake.     

Growth of young apple trees in relation to reserve nitrogen and carbohydrates

Bench-grafted Fuji/M.26 apple (Malus domestica Borkh.) trees were fertilized with a nutrient solution (fertigation) containing 0, 2.5, 5, 7.5, 10, 15 or 20 mM nitrogen (N) in a modified Hoagland's solution from June 30 to September 1. In mid-October, half of the trees in each N treatment were sprayed twice with 3% urea, 1 week apart. The remaining trees served as controls. All trees were harvested after leaf fall and stored at 2 degrees C over winter. One group of trees from each treatment was destructively sampled before bud break to determine amounts of reserve N and total nonstructural carbohydrates (TNC); the remaining trees were transplanted to N-free medium in the spring. These trees were supplied with Hoagland's solution with or without 10 mM N (from 15N-depleted NH4NO3) for 60 days, starting from bud break. With increasing N supply from fertigation, tree N concentration increased, whereas TNC concentration decreased. Foliar urea applications increased tree N concentration and decreased TNC concentration in each N fertigation treatment. There was a negative linear relationship between tree N concentration and TNC concentration. Irrespective of whether N was provided the following spring, trees with high N reserves but low carbohydrate reserves produced a larger total leaf area at the end of the regrowth period than trees with low N reserves but high carbohydrate reserves. The pooled data on reserve N used for new growth showed that, regardless of the spring N supply, there was a linear relationship between total N accumulated in the tree during the previous season and the amount of reserve N remobilized for new shoot and leaf growth. About 50% of tree N content was remobilized to support new shoot and leaf growth over the range of tree N status examined. We conclude that the initial growth of young apple trees in the spring is determined mainly by reserve N, not reserve carbohydrates. The amount of reserve N remobilized for new growth in spring was proportional to tree N status and was unaffected by current N supply.     

Relationships between stem diameter, sapwood area, leaf area and transpiration in a young mountain ash forest

We examined relationships between stem diameter, sapwood area, leaf area and transpiration in a 15-year-old mountain ash (Eucalyptus regnans F. Muell.) forest containing silver wattle (Acacia dealbata Link.) as a suppressed overstory species and mountain hickory (Acacia frigescens J.H. Willis) as an understory species. Stem diameter explained 93% of the variation in leaf area, 96% of the variation in sapwood area and 88% of the variation in mean daily spring transpiration in 19 mountain ash trees. In seven silver wattle trees, stem diameter explained 87% of the variation in sapwood area but was a poor predictor of the other variables. When transpiration measurements from individual trees were scaled up to a plot basis, using stem diameter values for 164 mountain ash trees and 124 silver wattle trees, mean daily spring transpiration rates of the two species were 2.3 and 0.6 mm day(-1), respectively. The leaf area index of the plot was estimated directly by destructive sampling, and indirectly with an LAI-2000 plant canopy analyzer and by hemispherical canopy photography. All three methods gave similar results.     

Tree Mortality,Needle Biomass Recovery and Growth Losses in Scots Pine Following Defoliation by Diprion pini (L.) and Subsequent Attack by Tomicus piniperda (L.)

Tree mortality and growth losses following insect defoliation are poorly documented in Scandinavia. In 1990-1991, Diprion pini (L.) caused extensive defoliation to Scots pine in Lauhanvuori national park and surrounding areas in south-western Finland. Most trees lost all their foliage in 1990. In 1991, the outbreak area was sprayed with diflubenzuron (Dimilin®), except in the national park, where trees were severely defoliated again. No further defoliation occurred in 1992. In spring 1993, sprayed trees had ca 30% foliage, whereas unsprayed trees on average carried less than 10% of full foliage. The latter trees were susceptible to attack by Tomicus piniperda (L.), whereas the former largely escaped beetle attack. Beetle attacks peaked in 1993, and depletion of suitable host trees probably terminated the beetle outbreak in the area. Two years of severe defoliation resulted in substantial tree mortality and growth losses. In spring 1997, these unsprayed stands had suffered a ca. 50% loss in basal area which was mainly because of mortality, and about half of the dead trees had been attacked by T. piniperda. Surviving trees had ca 50% of full foliage, and radial growth had still not recovered. Basal area growth was reduced by 40-70%, depending on the amount of foliage left after the second year of defoliation. In contrast, tree mortality and beetle attack in the sprayed stands were negligible, and these trees had recovered full foliage and radial growth by spring 1997. Thus, one year of total defoliation resulted in an estimated loss in basal area growth of approximately 30% during ca. 5 yrs. In conclusion, the spraying operation was economically justified, as it prevented substantial tree mortality and reduced growth losses.     

Direct seeding of native trees and shrubs in low rainfall areas and on non-wetting sands in South Australia

Seeds of common endemic species of Acacia, Callitris, Eucalyptus and Melaleuca were sown at 12 sites in Southern Australia in 1994 and 1995 to determine the role of soil stabilisers, fertilisers, time of seeding, herbicides, ripping and soil preparation with a V-blade or a disc in improving the reliability of direct seeding in Mediterranean type climates with low rainfall. Rainfall in 1994 was below average with 140 mm at the northern sites (55% of the average) and 300 mm at the southern sites (74% of the average) and only Acacia was successful with at least 3 plants/10 m present at the end of spring at eight sites and a survival rate after the first summer of 43%. In 1995 at least 3 plants/10 m of Acacia and Eucalyptus spp. were present at the end of spring at eight sites, with at least 3 plants/10 m of Melaleuca at six sites and at least 3 plants/10 m of Callitris at only three sites. Melaleuca had the highest overall survival rate at the end of summer with 52% compared to Acacia 42%, Eucalyptus 41% and Callitris 29%. Sowing two to three weeks after the opening rains (May at most sites) with good weed control gave the best results. Plant survival over the summer was reduced by 40% where weeds were not controlled by a herbicide. Ripping or fertiliser did not improve success. Ground preparation with an 80 cm wide V-blade generally produced better results than using a 25 cm wide disc except for Melaleuca. The effect of bitumen was variable in the trials, but appeared to be beneficial on wind eroded sites. The results indicate that direct seeding of trees and shrubs can be carried out in Mediterranean type climates with 250 to 425 mm average annual rainfall including on soils that are water repellent. This technology could be used for large scale revegetation in areas of the world with low rainfall Mediterranean type climates that have been largely denuded of trees and shrubs. This revised version was published online in August 2006 with corrections to the Cover Date.     

Stem respiration in a closed-canopy upland oak forest

Stem respiration was measured throughout 1993 on 56 mature trees of three species (Quercus alba L., Quercus prinus L., and Acer rubrum L.) in Walker Branch Watershed, Oak Ridge, Tennessee. A subset of the trees was remeasured during 1994. Diameter increments, stem temperatures and soil water were also monitored. Respiration rates in the spring and summer of 1993 tracked growth rate increments, except during a drought when growth dropped to zero and respiration increased to its highest rate. During the dormant season, rates of total stem respiration (R(t)) tended to be greater in large trees with thick sapwood but no such trend was observed during the growing season. Before and after the growing season, respiration rates correlated well with stem temperatures. Estimated values of Q(10) were 2.4 for the two oak species and 1.7 for red maple. The Q(10) values were used along with baseline respiration measurements and stem temperatures to predict seasonal changes in maintenance respiration (R(m)). In red maple, annual total R(m) accounted for 56 and 60% of R(t) in 1993 and 1994, respectively. In chestnut oak, R(m) accounted for 65 and 58% of R(t) in 1993 and 1994, respectively. In white oak, R(m) accounted for 47 and 53% of R(t) in 1993 and 1994, respectively. Extrapolating these data to the stand level showed that woody tissue respiration accounted for 149 and 204 g C m(-2) soil surface year(-1) in 1993 and 1994, respectively.     

Influence of Cattle Stocking Rate on Browsing of Norway Spruce in Subalpine Wood Pastures

In the Swiss Alps, 15% of Swiss mountain forests are grazed during summer, mainly by cattle. The forest laws of various Swiss cantons characterise forest grazing as a detrimental form of land use and stipulate that this grazing practice should be restricted. However, little is known about tree damage actually caused by cattle. Seven subalpine ranges in the Swiss Canton Grisons, grazed by cattle at different stocking rates, were investigated. The condition of naturally regenerated young trees (Picea abies (L.) Karst.) was assessed before and after the cattle grazing period. In order to characterise the influence of wild ungulates on the young trees during winter, the assessment of tree condition was repeated in the proximate spring. In total, 4% of the young trees were browsed on the apical shoot, 10% were browsed on lateral shoots, 13% of the trees showed other damage. The variation among ranges could almost completely be explained by the cattle stocking rate (livestock units per hectare). During winter, wild ungulates browsed 3 times as many young trees as the cattle during summer. The results suggest that cattle stocking rates on subalpine wood pastures should not exceed one livestock unit per hectare in order to avoid intensive browsing and other damage by cattle on young Norway spruces.