Pollen as Food for the Predatory Mites Iphiseius Degenerans and Neoseiulus Cucumeris (Acari: Phytoseiidae): Dietary Range and Life History

Although all known phytoseiid mites (Acari: Phytoseiidae) are predators of mites or small insects, many readily feed and reproduce on pollen as well. This ability to feed on food from plant origin increases their survival during periods when prey is locally sparse, but might occur at the expense of the ability to utilize food as efficiently as specialized predators. In this study we compare two predatory mite species used as biological control agents against thrips, Neoseiulus cucumeris and Iphiseius degenerans, with respect to (1) the range of pollen species that may serve as food sources for a sustained oviposition; and (2) the life history and expected intrinsic growth rates on some suitable pollen diets. The results show that I. degenerans is, compared to N. cucumeris, able to utilize a larger proportion of approx. 25 pollen species tested, but does not show equally high ovipositional rates as N. cucumeris. Consequently, the highest intrinsic growth rate for I. degenerans (0.21 day ^–1) will be surpassed by N. cucumeris.     

桑树对花叶病抗性遗传规律的研究

用７个母本、５个父本品种,按ＮＣＩＩ杂交设计,进行桑树对花叶病抗性的遗传分析。首次证明：桑树对花叶病的抗性具有数量遗传特点,符合加性－显性模型,主要受加性基因控制,广义遗传力和狭义遗传力中等,一般配合力显示绝对优势,具有超显性现象。母本品种含有比父本品种更多的显性基因     

A new Y-tube olfactometer for mosquitoes to measure the attractiveness of host odours

The behavioural responses of flying western flower thrips (Frankliniella occidentalis Pergande) (Thysanoptera: Thripidae) to the colour yellow and the odour anisaldehyde were examined. In a wind tunnel, upwind flight by female thrips was common in an airflow of 0.11 m s^–1 but was impeded at 0.22 m s^–1. In the absence of anisaldehyde, flying female thrips exhibited an oriented response towards a yellow cue in the wind tunnel at a wind speed of 0.11 m s^–1. The main response of females to anisaldehyde in the wind tunnel was flight inhibition. There was no evidence of an odour-induced visual response, an odour-induced anemotactic response or chemotaxis by female thrips to anisaldehyde in wind tunnel bioassays, but chemokinesis was implicated. With a matrix of yellow or black water traps with and without anisaldehyde in a greenhouse sweet pepper crop, yellow traps with anisaldehyde caught more thrips adults than yellow traps without anisaldehyde, black traps with anisaldehyde and black traps without anisaldehyde (1.3, 28 and 721 times for males respectively and 2.4, 9 and 117 times for females, respectively). Differences between respective traps were statistically significant in almost all cases. Trapping experiments using a centre-baited trap design to reduce the interaction of anisaldehyde between baited and unbaited traps were undertaken in tomato and sweet pepper greenhouse crops. When the spatial distribution of the thrips adult population within the greenhouse was taken into account, yellow water traps with anisaldehyde caught between 11 and 15 times more female and 3 and 20 times more male F. occidentalis adults than yellow traps without anisaldehyde.     

苜蓿叶片水杨酸含量与其蓟马抗性的关系

采用不同抗蓟马特性的苜蓿品系,于不同蓟马虫口密度下测定苜蓿水杨酸含量和虫害程度,以明确苜蓿叶片水杨酸含量与其抗蓟马特性的关系.结果表明,苜蓿叶片游离态、结合态水杨酸含量均与苜蓿抗蓟马特性密切相关;高抗品系(抗蓟马品系)的水杨酸初始含量(0.539 mg·g-1)高于低抗品系(0.403 mg·g-1);与较低抗品系相比,高抗品系受害器官(叶)水杨酸含量随虫口密度和危害点面积的增大而增加相对缓慢,而随危害指数的增大而增加较快(3.84倍).可见,水杨酸主要是间接增强苜蓿对蓟马的抗性;高抗蓟马苜蓿品系能通过快速获得较高水杨酸含量来阻碍被危害伤口的扩大,降低其受危害程度,促使自身产量和品质提高.     

九种金属离子对桑椹红色素稳定性影响的研究

本文报道Fe~(2+),Fe~(3+)……Ca~(2+)等9种金属离子对桑椹红色素稳定性影响的研究。结果表明:Fe~(2+),Fe~(2+),Cu~(2+),Zn~(2+)对该色素颜色的稳定性有不利影响;Mg~(2+),Al~(3+),K~+,Na~+,Ca~(2+)等5种金属离子有增强其吸收值的作用,其中Al~(3+)增色作用最为明显,Ca~(2+)护色作用较为突出,但它们的作用都随时间延长而逐渐降低。     

入侵害虫西花蓟马及其他8种常见蓟马的分子鉴定

用PCR产物直接测序法对入侵害虫西花蓟马和其他8种蓟马的线粒体 COⅠ基因433 bp片段测序，获得62个个体的序列。分子数据分析显示： 种内个体间平均遗传距离在0～0.005之间，2003年在北京发现的西花蓟马与欧洲等地区报导的西花蓟马不存在明显的遗传差异； 9种蓟马种间平均遗传距离为0.213。构建的NJ树可以很好的显示蓟马的聚类，物种各单元型最初分支自展值均达到100%。结果表明，基于PCR及直接测序技术的分子鉴定可以达到准确鉴定蓟马物种之目的。     

Initial verification of the resistance management strategy for Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) in Australia

Shortly after the initial detection of western flower thrips (WFT), Frankiniella occidentalis (Pergande), in Australia during 1993 a resistance management strategy based on the alternation of chemical groups was implemented. This study aimed to verify this strategy by field testing α-cypermethrin against WFT with and without chemical alternation. Up to 114 times α-cypermethrin resistance (at LC50) was detected and resistance increased with and without chemical alternation; however, chemical alternation did significantly reduce numbers of thrips compared with a nonalternation strategy. Resistance has the potential to undermine the sustainable use of those chemicals to which there is no current detectable resistance. Consequently, chemicals with a high frequency and level of resistance against WFT need to be identified through monitoring and quickly eliminated from WFT chemical control recommendations.     

西花蓟马检测鉴定技术研究进展

西花蓟马是一种世界性的入侵害虫,2003年首次在北京发现,目前仅在我国局部地区发生。其危害严重,潜在适生区广,且具有进一步扩散蔓延的趋势。快速准确的检测鉴定技术是防止其进一步扩散蔓延,保障我国农业生产健康发展的必要前提。综合相关报道,用于西花蓟马的检测鉴定技术包括传统的形态学特征鉴定法、由此衍生的计算机软件识别法,以及分子检测技术,如RAPD-PCR法、DNA序列分析法、PCR-RFLP法、SCAR分子标记技术、实时荧光定量PCR检测技术以及蛋白质分析技术等。其中,基因芯片和DNA条形编码技术作为新兴的物种鉴定手段,在西花蓟马等入侵物种的检测鉴定中具有广阔的应用前景。     

Pathogenicity of three entomopathogenic nematodes against the onion thrips,Thrips tabaci Lind. (Thys.; Thripidae)

Pathogenicity of a native isolate of Steinernema feltiae (H1) and two exotic strains, Heterorhabditis bacteriophora and Steinernema carpocapsae was assessed under laboratory conditions using different concentrations i.e. 4000, 6000, 8000 and 10,000 infective juveniles/ml against second instar larvae, prepupa and pupa of Thrips tabaci Lindeman. The mortality data were recorded 24 and 48?h post-inoculation. The highest mortality rate was recorded for prepupa (62%) than second instar (12.5%) by H. bacteriophora and S. carpocapsae, respectively, 24?h after treatment. No significant differences were found in mortality between prepupa and pupa with increasing the nematodes concentrations (from 4000 to 10,000 nematode/ml) but increasing nematode concentrations increased the mortality of second instar. At the end of the experiment (48?h.), S. feltiae H1 caused the highest mortality on second instar larvae (74%), whereas all other species caused 80–83% mortalities on pupa. This study suggests that native isolate of S. feltiae (H1) had high potential to infect soil-dwelling stages of T. tabaci.     

Silkworm Growth and Silk Yield on Selected Supplemented/ Un-supplemented Mulberry Varieties

ABSTRACT Sericulture has been on developing foot hills till today in Pakistan. It is for the past few years that this industry has received recognition through greater research on the nutritional aspects. Various experiments i.e., nutritional supplementation and searching alternate food plants have been on way with varying degree of success. The present approach includes the very much neglected aspect of trying mulberry varieties and working out their impact on the silkworm growth/ development and silk yield. In Pakistan three varieties of mulberry Morus alba, M. nigra and M. indica are commonly found, these were selected for the present studies and the already established mineral dose 0.2 %N +0.1%P+0.3%K+0.1%Ca+0.15%Mg+0.15%Mn was supplemented to them through dipping method. Amongst the so designed nine treatments those in which the silkworm larvae were fed on M. nigra leaves in any form /combinati-yielded best results, as the larvae in these treatments consumed more food (73.71 gm/10 larvae) and converted maximum (77.22%) of it into body matter. This improved silkworm growth, a primary parameter for increasing the over all production and resulted in better cocoon size which weighed heavier (2.43 gm/cocoon and 1.10 gm/shell) as compared to rest of the test treatments (0.67 and 0.70 gm/shell on M. alba and M. indica , respectively).