中牟县空陆联合防治春尺蠖

前不久的一天,河南省中牟县仓砦村村北杨树林上空,一架飞机在树梢上掠过,只见杨树食叶害虫——春尺蠖,像喝醉了酒似地纷纷掉落. 在春尺蠖初龄幼虫期,为及时全面减低春尺蠖虫口密度,有效控制春尺蠖的发生和危害,河南省中牟县林业局租用"蓝翔"飞机,组建专业队,空陆联合防治杨树食叶害虫春尺蠖.     

洪洞县春尺蠖的发生与防治研究

笔者对春尺蠖从成虫羽化、产卵、孵化、幼虫危害、老熟幼虫入土化蛹的整个过程进行了监测,探讨了在成虫期和幼虫期涂药环防治、喷药防治、喷烟防治等防治方法。2013年春尺蠖成虫死亡率达到62.2%,幼虫死亡率达到97.4%,防治效果显著,基本控制了春尺蠖的危害。最后,在此基础上讨论了成功防治春尺蠖的经验和今后防治工作的发展方向。     

航空喷雾20%氯虫苯甲酰胺悬浮剂防治美国白蛾试验

为明确20%氯虫苯甲酰胺悬浮剂防治美国白蛾幼虫的最适用药剂量和最佳防治龄期,开展了直升机超低容量喷雾防治试验。结果表明,20%氯虫苯甲酰胺悬浮剂对美国白蛾2~3龄幼虫具有较好的速效性和较长的持效期。在120 m L/hm~2和150 m L/hm~2用药剂量下,美国白蛾2龄幼虫虫口减退率施药后2 d分别为96.5%和100%;3龄幼虫施药后4 d分别为97.5%和99.0%;4龄和5龄幼虫施药后6 d分别为77.8%、83.1%和99.8%、77.9%,施药后7 d均达100%;施药后8 d投放5龄幼虫,7 d后虫口减退率仍在80%左右。在90 m L/hm~2用药剂量下,施药后7 d,仅2龄幼虫虫口减退率达到100%,3龄幼虫虫口减退率为68.6%,4龄和5龄幼虫虫口减退率只有40%左右。航空喷雾20%氯虫苯甲酰胺悬浮剂防治美国白蛾幼虫的最适用药剂量为120~150 m L/hm~2,持效期可达15 d,最佳防治龄期为2~3龄。     

为害刺槐的几种尺蠖生物学特性及防治技术研究

通过对刺槐眉尺蠖、春尺蠖、桑褶翅尺蠖等3种尺蠖野外调查和室内饲养,3种尺蠖均为1年发生1代,以蛹在树冠下土壤中越夏越冬,均以幼虫取食叶片危害,危害高峰期在3～4龄,用人工、化学的综合防治方法,防治后使试验防治区刺槐被害株率由防前100%下降到13%,单株虫口密度由防前214头下降到11头。     

八角尺蠖幼虫形态特征的测察

八角尺蠖是广西八角林木主要害虫,它连续或间歇成灾,经常导致八角果的减产或失收,是八角林农特别关注的食叶害虫。八角尺蠖以幼虫危害叶片,幼虫每年有四代,各代幼虫期是防治的关键时期。幼虫共7龄,其中第六龄、第七龄的大龄阶段是幼虫的暴食期,对林木的危害最大。要减少幼虫对八角林木的危害,就必需在中、幼龄阶段对虫口进行控制,采取化学或生物等手段实施防治。因此,在调查林木虫口密度的同时,准确地判断八角幼虫的龄期显得十分重要,它有助于合理地决定防治的时间,维护八角林木正常生长,保证八角果的收成。     

苏云金菌粉防治榆尺蠖效果好

榆尺蠖又称春尺蠖,是榆树的主要害虫。四子王旗榆树种植区由于榆尺蠖的侵害,严重地影响了树木的正常生长。从一九八二年起,我们采用苏云金菌粉和化学农药相结合的办法,对榆尺蠖发生林地进行了防治,榆尺蠖死亡率达98％以上,而且两三年内榆尺蠖不再成灾。榆尺蠖在四子王旗一般四月二十日前后孵化,五月五日左右孵化结束。幼虫从孵化到化蛹大约三十天。由于卵的孵化期不一致,我们放过一龄幼虫出现盛期,从二龄幼虫出现盛期起防治,这时一般在五月十日以后。施药方法:将含孢量为100亿/克的苏云金菌粉100倍液和D—M合剂2000倍液制成混     

森林病虫害的预测预报

第二讲 森林害虫预测预报方法（续） 3.发育进度预测法 发育进度预测法又叫历期推算预测法。这种方法是根据害虫的发育进度,加上相应的虫态历期,推算以后各虫态的发生期。例如,春尺蠖最佳防治时间即三龄幼虫盛期的预测公式为: 三龄幼虫盛期=成虫羽化盛期+卵前期+卵历期+1.2龄幼虫历期 首先要调查得到准确的成虫羽化盛期,再根据气象预报预测出成虫的卵前期、卵历期和1.2龄幼虫历期,从而推算出三龄幼虫盛期,定为防治的最佳时间。 成虫的卵前期（羽化后至产卵）与温度     

土农药4115防治油茶尺蠖

我局于1975年4月5日至16日在七里坪公社七星大队与贫下中农一道开展了用土农药4115防治油茶尺蠖试验,防治面积达450亩。4115防治油茶尺蠖1—2龄幼虫效果显著,死亡率分别为100%和90%,而3—4龄幼虫则只有64%和16%,但总死亡率仍达80%以上。因此,我们认为只要准确地掌握油茶尺蠖的幼虫龄期,抓住在1—2龄(最迟2—3龄)时用药,将能达到较好的效果。     

落叶松尺蠖生活史及防治研究

落叶松尺蠖是落叶松的主要食叶害虫,在五台山地区一年发生一代。该幼虫期共5龄,危害期35～42天,以卵在当年的球果鳞片和树皮缝间越冬.卵期长达230～240天.郁闭度为0.6～0.8,15～20年生落叶松林,虫口密度在20头/株以下时,不需要防治,虫口密度在200头/株以上时,需进行防治。7月上旬,在林地内可见20%的幼虫患病死亡。用溴氰菊酯25000倍液和速灭杀丁15000倍液防治效果分别达到96.35％、95.9％。我们于1989年～1990年先后在五台山林场对该虫生物习性进行了研究,并做了防治试验,现将结果整理如下:1.生物学特性的研究该虫在五台山地区一年发生一代,以卵在当年的球果鳞片和树皮缝间越冬,次年4月下旬末5月初越冬卵开始孵化,幼虫呈聚集分布,其分布的基本成分是疏松的个体群进行取食落叶松针叶,三龄后食量增大,幼虫危害期35～42天。幼虫期共五龄,第一龄历时5～8日,二龄4～6日,三龄4～5日,四龄6～7日,五龄13～15日。老熟幼虫于6月下旬就停止取食,开始吐丝下垂,进入预蛹期,经一周左右,下地爬行片刻,钻入土中,做一个长圆形土茧,于6月下旬末7月上旬就开始化蛹。化蛹一般在树根部周围1.5米范围内,土层深度不超过65厘米,蛹期长达65～86天。7月中旬成虫羽化,成虫羽化时多在早上。雌虫足长,善于爬行,羽化后即爬行上树.     

湘乡市第一代马尾松毛虫发生情况测报初探

马尾松毛虫是湘乡市的主要林业有害生物。2017年度,本试验通过频振式诱虫灯诱集越冬代马尾松毛虫成虫进行种群动态监测,结果表明:5月30日是越冬代马尾松毛虫成虫上灯的高峰期,用期距法预测第一代3龄幼虫高峰期为6月19日,为最佳防治时期。有效基数法和危害程度预测数据均表明湘乡市月山镇群乐村2017年第一代马尾松毛虫虫口基数过大,建议提前做好防治准备工作,避免翌年越冬代幼虫暴发成灾。     

Armillaria ostoyae in managed coniferous forests in Kastamonu in Turkey

Although several Armillaria species have been reported in Turkey, there is little information about their ecology in Turkish forests. In this study, we investigated five forest stands, approximately 5–74 ha in size, in Kastamonu province in the Black Sea Region of Turkey for the presence of Armillaria species in stumps and logs. The stands were mixed Abies nordmanniana ssp. bornmülleriana and Pinus sylvestris forests managed using a selective cuttings system; the proportion of fir in the total number of stems and stumps ranged from 36 to 98%. Based on sequence analysis of the internal transcribed spacer and intergenic spacer regions of the rDNA, all rhizomorphs sampled from the stumps and logs were of Armillaria ostoyae. The size of the genets was estimated with random amplified microsatellites analysis of the isolates and ranged from single stumps to approximately 450 m². One to seven genets were found in each stand. These results indicate that the genets had arisen from spores and vegetative spread was limited on most sites.     

上海中央公园特大银杏树白蚁防治探讨

通过对上海松江中央公园内65株特大银杏树白蚁为害情况的调查,发现该公园银杏受害率为100%,其中存在活白蚁的银杏占总量的56.9%,采用毒土处理、粉剂疗法、建立白蚁监测点等措施,经过两次灭杀,活白蚁的灭杀率达到92.3%和93.3%,从而使存在活白蚁银杏树的比例从56.9%下降到2.7%,白蚁发生情况明显降低。       

我国食品中农药残留研究进展

随着人们安全健康意识提高,食品中农药残留问题更加受到重视,本文综述了样品预处理研究进展及农药残留快速检测技术研究进展,并简单分析介绍各种方法的优缺点。     

建平半干旱地区石质山地造林技术研究

研究了不同植物在石质山地的造林成活率、土壤化学性质随造林年限的变化和造林措施对土壤化学性质和植物胸径、树高年净生长量的影响。结果表明：不同植物在石质山地的成活率在21%～85%之间,其中白榆和沙打旺的成活率分别为81%和85%,而小叶杨、刺槐、栾树的成活率均在70%左右;植被能明显提高石质山地不同土层的有机质、全N、P2O5含量,但提高程度随土层深度、养分种类和造林年限的不同而不同;在同一土层,生物复合肥料、菌剂和保水剂均显著提高土壤有机质含量（p〈0.01）并显著降低土壤P2O5含量（p〈0.01）;只有保水剂可引起土壤全K含量的明显升高;生物复合肥料、菌剂和保水剂均显著提高白榆、小叶杨、刺槐、栾树树高和胸径的年净生长量,但保水剂的提高程度最高。     

植物DNA甲基化研究进展

植物经常暴露在各种生物和非生物的胁迫之下,这些胁迫会影响植物的生长发育和繁殖并最终导致植物死亡。为了抵御不利的环境条件,植物已经进化出复杂而精细的网络来感知胁迫并激活防御系统。为此,植物激活许多信号转导通路,这些信号转导通路可以改变一些胁迫响应基因的表达,从而引起植物形态、生理和生化的改变以适应逆境。DNA胞嘧啶甲基化是高等真核生物的主要表观遗传机制之一,在维持基因组稳定性和调节基因表达方面起着关键作用。表观遗传变异比遗传变异更为灵活。一旦环境条件发生变化,为了适应新的环境植物都会发生表观遗传的改变。许多研究表明DNA甲基化参与植物的发育和应激反应。基于相关研究对DNA甲基化进行了综述,对植物逆境胁迫有重要意义。     

木材碳封存研究进展

碳封存可以分工业封存和生物封存, 工业封存包括地质封存、海洋封存、矿石碳化以及工业循环利用, 这些方法能快速回收CO₂, 但工艺流程技术复杂, 成本较高。木材碳封存是生物碳封存的一种类型, 树木光合作用吸收的碳主要存贮在木材中。运用木材密度、微密度等检测仪器, 通过确定木材密度变化, 结合其含碳率来计量木材的碳封存过程以及封存过程中碳的分配格局, 同时研究其与环境因子的相关性, 可以为研究森林的碳吸收动态提供便捷的方法和科学的依据。     

Tree regeneration in patch cutting in Norway spruce stands in northern Finland

The study focused on the success of regeneration on patch cuts in spruce-dominated stands in terms of stocking and tree height. It was based on an experiment in the Kainuu region in northern Finland. The experimental design included 8 stands with 58 clearcut patches of variable size (0.09–0.37?ha), on which either natural regeneration without site preparation or site preparation and planting of Scots pine was applied. A regeneration survey was conducted 13–15 growing seasons after treatments. Patches without site preparation had been restocked quite well from natural seed sources. The average number of trees was about 11,000?ha^?1, of which 1700?ha^?1 crop trees. With site preparation and planting, the stocking levels were also very high, 25,000 and 2100?ha^?1, respectively. One hundred percent of the planted patches and 75% of the naturally regenerated patches had an acceptable density. Restocking was equally good across the range of patch sizes. Tree growth had been somewhat slower in the smallest patches than in the largest ones in the range. Natural regeneration was capable of yielding good regeneration results in most patches, especially when site preparation was applied. Stocking levels and height development were higher yet in the planted patches.     

Changes in micropores in dry wood with elapsed time in the environment

To investigate the changes in microstructures of wood with elapsed time in the environment, CO₂ adsorption onto dry wood was measured at ice-water temperature (273 K) for samples aged from 0.1 years to over 1000 years. The micropore size distribution was obtained using the Horvath-Kawazoe method. Micropores smaller than 0.6 nm in wood decreased in number with elapsed time in the environment, and a negative correlation was found between cumulative pore volume for pores smaller than 0.6 nm and elapsed time in the environment. Cumulative pore volume in the 1000-year sample was almost half of that in the 0.1- year sample. Micropores smaller than 0.6 nm in wood with a few decades or more of elapsed time increased in number after rewetting and drying. Consequently, microstructures of wood with longer time elapsed in the environment were considered to be more stable, because of longer-term thermal motion and possibly more repeated moisture adsorption and desorption and/or temperature variation in the environment.     

Natural regeneration in patch clear-cutting in Picea abies stands in Southern Finland

Abstract

The success of natural regeneration on patch clear-cuts in Norway spruce stands in Southern Finland was examined in terms of stocking and tree height. The experiment was established in mature spruce stands in the submesic Myrtillus (MT) site type. In each of the eight study sites, three plots were treated with clear-cutting and planting, clear-cutting with partial tree retention and planting, and patch clear-cutting without site preparation, respectively. In three of the study sites, one plot with patch clear-cutting and site preparation was established. Each plot was 1 ha, out of which three patches of 40×40 m were clear-cut in the patch treatments. 10–11 years after cutting, the patches had on average 1316 crop trees ha^–1, of which 91% were spruces. Some 27% of the stands were up to the target stocking level (≥1600 ha^?1), and 36% were at least satisfactory (≥1300 ha^?1). Site preparation did not yield greater stocking levels on patches, but that result is ambiguous due to a difference in initial stocking. The average spruce tree height in the patches (0.76 m) was much smaller than in the case of clear-cutting and planting (2.42 m). In conclusion, the patches had been restocked tolerably well with spruce and birch for practical purposes during the 10- to 11-year period, but the regeneration process had been very slow compared to clear-cutting and planting.