高粱蚜灰色灾变长期预测模型

本文应用灰色系统灾变预测理论建立了吕梁地区高粱蚜发生量预测模型．     

Numbers of pink sugarcane mealy bug, Saccharicoccus sacchari (Cockerell) (Hemiptera: Pseudococcidae), differ within seasons and among regions and stages of the sugarcane crop cycle

Abstract  The pink sugarcane mealy bug (PSMB; Saccharicoccus sacchari ) is widespread on sugarcane globally. PSMB infest above-ground storage tissue as it develops, feeding on phloem and producing exudate. It is not known, however, whether the level of infestations is the same in different sugar growing regions, or how population size varies year to year within a region. Field surveys of the number of nodes infested were conducted over five seasons in three mill-regions in northern Australia (Macknade, Kalamia and Marian) on plant and ratoon crops. The pattern of infestation was very similar across seasons (only in 1 year of very low rainfall was the increase in population delayed). In all three regions the proportion of nodes infested was similar but reached the maximum 1 month later in the Marian region compared with the Kalamia and Macknade regions. The Kalamia region was distinguished by the rapid decline in the number of nodes infested down to a very low level by March. In the Macknade region mealy bugs persisted at higher levels than the other two regions. The PSMB infestation started earlier and was much greater in ratoon crops than plant crops throughout the sampling period. The differences were more pronounced in the Macknade and Marian districts. These observations provide a firm basis from which future strategies to control PSMB can be developed.     

新侵入害虫蔗扁蛾生活史

蔗扁蛾Opogona sacchari (Bojer)是一种新传入我国的危险性外来害虫。在温度25.71±2.71℃和相对湿度(74.95±5.02)%的条件下,完成一个世代需要66～135天,全年约可发生4代。幼虫期是历史时最长的虫态,需要37～75天,共7龄,是该虫的为害虫期。成虫的交配和产卵需要一定的空间,产卵量为253.05±65.18 (n=20) 。     

高粱抗高粱蚜的生化基础

高粱中的可溶性总氮、可溶性总糖和绝大部分游离氨基酸,特别是必需氨基酸,在感性品种中的含量显著地比抗性品种中的含量高.感性品种叶液微偏酸,抗性品种近中性.多元回归分析表明,高梁对高粱蚜Melanaphis sacchari(Zehntner)的抗性与可溶性总氮、可溶性总糖和游离氨基酸的含量呈反相关.     

Molecular detection of Gluconacetobacter sacchari associated with the pink sugarcane mealybug Saccharicoccus sacchari (Cockerell) and the sugarcane leaf sheath microenvironment by FISH and PCR

Molecular tools for the detection of the newly described acetic acid bacterium Gluconacetobacter sacchari from the pink sugarcane mealybug, Saccharicoccus sacchari Cockerell (Homiptera: Pseudococcidae), and in the sugarcane leaf sheath microenvironment were developed. G. sacchari specific 16S rRNA-targeted oligonucleotide primers were designed and used in PCR amplification of G. sacchari DNA directly from mealybugs, and in a nested PCR to detect low numbers of the bacteria from sugarcane leaf sheath fluid and cane internode scrapings. A sensitivity level of detection of 40-400 cells/reaction was obtained using PCR from exponentially grown bacterial cultures and of 1-10 cells in cane internode scrapings and leaf sheath fluid samples using nested PCR. The specificity of the primer set was demonstrated by the lack of amplification product formation in PCR by closely related acetic acid bacteria, including Gluconacetobacter liquefaciens, and Gluconacetobacter diazotrophicus. A Cy3 labeled probe for G. sacchari was designed and shown to be specific for the species. Investigation of the mealybug microenvironment by whole cell fluorescent in situ hybridization revealed that G. sacchari appears to represent only a minor proportion of the population of the microbiota in the mealybugs tested. This study has shown the usefulness of 16S rRNA-based molecular tools in the identification and detection of G. sacchari from environmental samples and will allow these tools to be used in further ecological research.     

Belowground organism activities affect plant aboveground phenotype, inducing plant tolerance to parasites

Soil fauna activities are probably more important than currently acknowledged in determining individual plant response to stresses and overall plant diversity. Here we demonstrate that the positive effect of earthworms on rice could be the result of a systemic effect on plant physiology. Moreover, this effect could improve tolerance to stressors such as parasitic nematodes. In a controlled experiment, an 82% decrease in the production of infested plants was suppressed when earthworms were present. Earthworms had no direct effect on nematode population size. In their presence, however, root biomass was not affected by nematodes and the expected inhibition of photosynthesis was suppressed. In the leaves, the expression of three stress‐responsive genes (coding for lipoxygenase, phospholipase D and cysteine protease) was modulated by the presence of belowground invertebrate activities. We document conflicting systemic effects of parasitic nematodes and beneficial earthworms, although we cannot precisely identify the mechanism involved. These results reveal the importance of non‐trophic belowground/aboveground interactions for plant health and response to stresses.     

Ecdysteroids in the adults and eggs of Opogona sacchari (Bojer), an invasive alien pest

In order to understand the composition and quantitative variation of ecdysteriods in the adults and eggs of Opogona sacchari (Bojer), an invasive alien pest, we analyzed the ecdysteroid composition and titers in the adult and egg of this pest. On day 4 after eclosion, the titer of ecdysteriods in the male adult was 0.080 ng/adult, much lower than 5.978 ng/adult in the female adult. During the development of ovaries, the titer of ecdysteriods was low on the first two days, and high in the late period, with the peak (10.48 ng/ovary) appearing on day 3. During the development of eggs, the titer of ecdysteriods was about 0.010 ng/egg from day 1 to day 3, and then decreased to 0.006 ng/egg on day 4. In both adults and eggs, three main components of ecdysteriods were found by identification of HPLC/RIA. They were 20-hydroxyecdysone, 26-hydroxyecdysone, and an unidentified component.     

广西云南玉米霜霉病病原菌订正

在我国文献中广西云南玉米霜霉病菌名称为Peronosclerospora maydis (Racib．)C. G.Shaw。但是我们观测病菌孢子囊为长椭球形;在13℃—28℃产孢温度范围内,随温度升高孢子囊长度增加而宽度基本不变,表明它不是P．Maydis,而是P．Sacchari (T．Miyake)Shirai ＆ K．Hara,或 P．Philippinensis (Weston)C．G．Shaw。以四种 Peronosclerospo-ra的DNA及广西云南病菌的DNA与探针pCLY83杂交的RFLP图谱进一步证实了此结果,并表明 P.sacchari 与 P．Philippinensis为同种异名。因此我国广西云南玉米霜霉菌名称应为 Peronosclerospora sacchari (T．Miyake) Shirai & K．Hara,现予订正。     

蔗扁蛾生物学特性及幼虫耐寒性初步研究

蔗扁蛾在江苏地区目前已发现 5个科、8种寄主 ;在扬州 1年发生 4代 ,以幼虫越冬 ;2 5℃下 ,利用寄主发财树饲养该虫 ,卵历期为 5 7d ,幼虫期为 3 4 4d ,蛹历期为 1 4 9d ,整个世代历期为 5 7 6d;不同季节高龄幼虫的过冷却点不同 ,分别为 :冬前 -4 3 6℃ ,隆冬 -6 44℃ ,冬后 -4 89℃ ;不同低温对蔗扁蛾幼虫死亡率影响很大 ,-2℃幼虫 72h后大都死亡 ,-5℃幼虫 48h全部死亡 ;在扬州地区 ,蔗扁蛾在室外安全越冬的可能性较小     

辽宁朝阳地区高粱蚜田间消长规律及防治适期

对辽宁省朝阳地区1989~2001年13年的高粱蚜Melanaphissacchari(Zehntner)的系统调查资料分析结果表明,该地区高粱蚜为间歇性发生,发生频率为60%左右。在不施农药的自然情况下,田间发生表现6个阶段,消长规律明显。中等发生年一般峰期日平均百株蚜量5~15万头,严重年25~60万头。各年度田间百株蚜量与蚜虫天敌单位呈极显著相关,天敌紧密跟随蚜虫。防治适期为7月25日~8月5日,个别发生较早的年份可以提前2~3d。