不同杀菌剂对小麦纹枯病和赤霉病的防治效果

为明确不同杀菌剂对小麦纹枯病、赤霉病的防治效果,在大田条件下以‘开麦21’为试验材料研究了12种杀菌剂对小麦纹枯病、11种杀菌剂对赤霉病的防治效果及对小麦产量的影响。结果表明:30%己唑醇悬浮剂76.5g/hm2、75%肟菌·戊唑醇水分散粒剂168.75g/hm2处理对小麦纹枯病的防效较好,拔节期病指防效(乳熟期枯白穗防效)分别为62.77%(56.21%)和60.58%(53.45%),小麦产量较对照分别增加27.65%和21.30%;48%氰烯·戊唑醇悬浮剂432g/hm2、25%氰烯菌酯悬浮剂750g/hm2处理对小麦赤霉病的防效较好,病指防效(病穗防效)分别为70.78%(56.57%)和68.84%(46.86%),小麦产量较对照分别增加25.44%和24.40%。综合分析,以上药剂可做田间大面积推广应用。     

植保飞防对小麦赤霉病的防治效果

为了筛选植保飞防对口药剂,验证植保飞防对小麦赤霉病的防治效果、作业效率,2017年在钟祥市石牌镇开展小麦赤霉病飞防试验。结果表明,400g/L戊唑·咪鲜胺EW、45%戊唑醇·咪鲜胺EW、25%咪鲜胺EW、吡虫啉+功夫+苯醚甲环唑+嘧菌酯SE、25%氰烯菌酯SC均适合作为小麦赤霉病植保飞防药剂。从防效和增产效果综合来看,25%氰烯菌酯SC是预防小麦赤霉病最佳药剂。植保飞防P20无人植保机日作业面积可达20hm~2~33.33hm~2,是农户精防作业的20倍~33倍,是常规自防作业的12倍~20倍。植保飞防与农户精防在防病增产效果方面没有区别,赤霉病飞防效率为66.76%~77.04%,较农户自防提高15.78%~26.06%,产量提高5.3%~21.3%。     

不同杀菌剂不同施用次数对小麦赤霉病的防效

在种植小麦赤霉病高感品种襄麦1321的田间进行施药试验。调查5种药剂:50%多菌灵可湿性粉剂、25%氰烯菌酯悬浮剂、25%咪鲜胺乳油、70%甲基硫菌灵可湿性粉剂、30%福美双可湿性粉剂分别喷施1~4次处理对小麦赤霉病的防治效果。结果表明,施药24h内降雨对氰烯菌酯的防效影响最大;咪鲜胺防效相对较差,不同施用次数的病指防效为42.51%~64.55%;多菌灵、甲基硫菌灵和氰烯菌酯施用3~4次的处理防效较高,病指防效均达70%以上;福美双的防效随施用次数增多而提高,施用4次的处理防效也达70%以上。     

助剂对小麦赤霉病大田飞防效果的影响

近几年,天门市小麦赤霉病发生严重。本文采用15%丙唑·戊唑醇SC(麦田喜)和25%氰烯菌酯SC(劲护)等药剂,使用农用无人机防治小麦赤霉病,并研究添加助剂麦霸与天飞沉降剂对飞防效果的影响以及减药作用。试验结果表明：15%丙唑·戊唑醇SC、25%氰烯菌酯SC的防效最高分别达51.42%和58.22%,以上两种药剂添加助剂麦霸与天飞沉降剂后防效最高分别达61.13%和68.04%,说明添加助剂有助于提高飞防效果;添加助剂并降低30%的农药量后,防治效果未显著下降。相同配比用量的农药,每667 m²兑水3 L的喷施防治效果要优于兑水1 L的喷施防治效果。     

25%氰烯菌酯悬浮剂防治小麦赤霉病试验

试验结果表明,供试药剂25%氰烯菌酯悬浮剂对小麦赤霉病的防效较好。在发病初期连施两次药基本能控制小麦赤霉病的为害,其内吸性较好,持效期较长。在试验剂量范围内对小麦生长发育无不良影响,是防治小麦赤霉病较理想的药剂。     

酸性氧化电解水防治小麦赤霉病田间试验

为探索酸性氧化电解水(以下简称电解水)防治小麦赤霉病田间效果,2018年在光山县开展电解水防治小麦赤霉病田间试验结果表明:电解水对小麦赤霉病的防效为60.19%;用电解水稀释2/3常规用药量20g/667m2的25%戊唑醇防效为71.05%比用清水稀释25%戊唑醇30g/667m2(全量)防效为67.60%高。方差分析,电解水与25%戊唑醇对小麦赤霉病的防治效果没有显著差异。电解水既可以替代化学农药也可以减量化学农药防治小麦赤霉病。     

不同类型农药对小麦赤霉病防治效果综合示范

为了筛选防治小麦赤霉病的高效低风险农药，选择4个小麦主推品种，分别使用麦甜+麦甜伴侣(20%氟唑菌酰羟胺SC+25%丙环唑SC)、喜多金(38%唑醚·氟环唑SC)、笑多收(45%戊唑·咪鲜胺EW)等3种不同类型的药剂进行赤霉病防治示范。结果表明，3种药剂对小麦赤霉病均有较好的防效，在4个小麦主推品种上平均防效分别为88.1%、81.5%、75.5%;其中，以麦甜+麦甜伴侣效果最好，且该药剂处理对小麦的增产幅度在5%以上，增产效果高于其它两种药剂处理。建议在生产实际中，推荐使用麦甜+麦甜伴侣(20%氟唑菌酰羟胺SC+25%丙环唑SC)防治小麦赤霉病，以便提高防效和小麦产量。     

不同药剂防治小麦赤霉病试验初报

采用我省小麦主产区常用的8种药剂及组合进行防治小麦赤霉病试验,筛选出优质高效农药。试验结果表明,防效最佳药剂为氰烯菌酯,达92.21%,增产和防效俱佳的是嘧菌酯+戊唑醇防效85.71,比对照增产42.75kg,其它嘧菌酯及其复配制剂防效也都在80%以上。     

2016年小麦赤霉病药剂防治试验

近几年来,小麦赤霉病受菌源、天气、品种等因素的影响,暴发频次增加,造成小麦减产。为生产上选择防治赤霉病的高效药剂,2016年用不同药剂对小麦赤霉病进行了田间药效试验。试验结果表明,除每667 m~2用40%多·酮可湿性粉剂120 g对小麦赤霉病的防治效果较差外,仅为55.93%,其他试验药剂对小麦赤霉病的防治效果较好。     

不同配比多菌灵与戊唑醇防治小麦赤霉病研究

在感病品种和中等肥力土壤条件下,分析多茵灵、戊唑醇不同比例混配对小麦赤霉病的室内活性和田间防效以及对小麦产量及DON毒素的影响。结果表明:多菌灵、戊唑醇2:1~7:1比例混配对小麦赤霉病菌均呈加和作用,多菌灵与戊唑醇4:1、5:1、7:1对小麦赤霉病的田间防效在60.3%~73.3%之间,小麦产量增加49.1%~72.2%,多菌灵:戊唑醇7:1比例混配在用药量较少的情况下防效与其他比例混配药剂防效相当,但3种配比处理间小麦产量和DON毒素并无显著差异(P0.05)。结合生产实际,48%戊·多悬浮剂、80%戊·多可湿性粉剂、40%戊·多悬浮剂在其中高剂量下在小麦扬花10%、小麦扬花100%时期各施用1次对小麦赤霉病有理想防效,具有推广意义。     

Hymenopteran Parasitoids on Fruit-infesting Tephritidae (Diptera) in Latin America and the Southern United States: Diversity, Distribution, Taxonomic Status and their use in Fruit Fly Biological Control

We first discuss the diversity of fruit fly (Diptera: Tephritidae) parasitoids (Hymenoptera) of the Neotropics. Even though the emphasis is on Anastrepha parasitoids, we also review all the information available on parasitoids attacking flies in the genera Ceratitis, Rhagoletis, Rhagoletotrypeta, Toxotrypana and Zonosemata. We center our analysis in parasitoid guilds, parasitoid assemblage size and fly host profiles. We also discuss distribution patterns and the taxonomic status of all known Anastrepha parasitoids. We follow by providing a historical overview of biological control of pestiferous tephritids in Latin American and Florida (U.S.A.) and by analyzing the success or failure of classical and augmentative biological control programs implemented to date in these regions. We also discuss the lack of success of introductions of exotic fruit fly parasitoids in various Latin American countries. We finish by discussing the most pressing needs related to fruit fly biological control (classical, augmentative, and conservation modalities) in areas of the Neotropics where fruit fly populations severely restrict the development of commercial fruit growing. We also address the need for much more intensive research on the bioecology of native fruit fly parasitoids.     

Brief Guide for Authors

正Journal of Arid Land(JAL)is an international journal(ISSN 1674-6767;CN 65-1278/K)for the natural sciences,sponsored by the Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences and Science Press.It is published by Science Press and Springer-Verlag Berlin Heidelberg bimonthly.JAL publishes original,innovative,and integrative research from arid and semiarid regions,ad     

The parasitoid complex ofLiriomyza cicerina on chickpea (Cicer arietinum)

Liriomyza cicerina (Diptera: Agromyzidae) is an important pest on chickpea in Turkey. The objective of this study was to determine the parasitoids and rates of parasitism ofL. cicerina on chickpea (Cicer arietinum L.) during the 2005 and 2006 seasons in ?anl?urfa province, Turkey. Leaves with mines were sampled weekly and kept in the laboratory to observe and count emerging leafminer and parasitoid adults. Eight parasitoid species were collected: the braconidsOpius monilicornis Fischer andOpius tersus Foerster and the eulophidsDiaulinopsis arenaria (Erdös) andNeochrysocharis formosa (Westwood), which occurred in both the winter and summer seasons;Diglyphus crassinervis Erdös,Neochrysocharis ambitiosa Hansson,Neochrysocharis sericea (Erdös) andPediobius metallicus (Nees), which occurred only in the summer growing areas.Diaulinopsis arenaria was the predominant parasitoid with 4–7.7% parasitism rate whileN. ambitiosa andO. monilicornis were the second and third most predominant species. The results of these trials show that sinceDia. arenaria occurred throughout every season, it could potentially be used for control of the leafminerL. cicerina.     

Plant–herbivore asynchrony necessitates augmentative releases of the exotic beetle,Zygogramma bicolorata,to enhance the biological control of P arthenium hysterophorus

Systematic information on the quantitative impact of Z ygogramma bicolorata on the biology of P arthenium hysterophorus is crucial as the seeds of this weed continue to germinate from the accumulated soil seed bank throughout the year in the form of different germinating flushes, while the activity of the beetle ceases during winter as it enters diapause. Therefore, plant–herbivore interactions need to be explored to develop predictions of the overall impact of the introduced beetle on the weed. The findings revealed that defoliation by Z . bicolorata had a significant impact on the plant height, density and flower production in flushes F ₃, F ₄ and F ₅, but not in F ₁ and F ₂ that exhibited longer periodicity, profuse branching, a longer flowering period and maximum flower production and contributed mostly to the existing seed soil bank. Therefore, total depletion of the existing soil seed bank was not possible. Consequently, the effect of augmentative field releases of laboratory‐reared beetles was explored on F ₁ and F ₂ in February for three consecutive years (2011–2013). Before initiating the trial, random soil samples were taken from the plots that were assigned to the paired treatments (i.e. with the beetle and without the beetle [insecticide‐treated]) and it was found that the seed bank in those samples did not differ. The single release of Z . bicolorata adults at five per plant at the six‐leaf stage significantly reduced the soil seed bank, compared to without the biocontrol agent, irrespective of the flushes at the end of the season.     

Effects of the saprophytic leaf mycoflora on growth and productivity of winter wheat

The effects of the saprophytic mycoflora and its interference with cereal aphids on growth and yield of winter and spring wheat was studied in field experiments in 1980, 1981 and 1982.Yields varied between 5000 and 8000 kg dry matter of kernels per ha. The effect of the saprophytic mycoflora on yield was determined in different treatments: A) no control measures against cereal aphids and saprophytic and necrotrophic fungi, B) no control of cereal aphids, control of saprophytic and necrotrophic fungi, C) control of cereal aphids and control of saprophytic and necrotrophic fungi, D) control of cereal aphids and stimulation of saprophytic mycoflora and E) control of cereal aphids, no control of saprophytic and necrotrophic fungi nor stimulation of saprophytic mycoflora.Considerable differences in top densities of saprophytic mycoflora (10 times as large in A and D as in B and C) were determined. The consequences of these differences for the growth and productivity of wheat were minor. A negative effect of saprophytic mycoflora on the yield could not be detected in 1981 and 1982, whereas a small positive significant effect was found in 1980. This stimulation may have been due to competition between necrotrophic fungal pathogens and saprophytic mycoflora. As a result of favourable weather conditions necrotrophic fungal pathogens were very numerous in 1980 and could form an important yield reducing factor. Yield levels may effect the importance of the necrotrophic and saprophytic mycoflora as yield reducing factors. Additionally, in the presence of aphid honeydew captafol was found to be relatively ineffective against saprophytic fungi.     

Relationship Between Production of the Phytotoxin Prehelminthosporol and Virulence in Isolates of the Plant Pathogenic Fungus Bipolaris sorokiniana

A gas chromatographic method was developed to quantify the phytotoxin prehelminthosporol, which is a sesquiterpene metabolite of the plant pathogen Bipolaris sorokiniana. The toxin was extracted from mycelium or culture filtrates, pre-cleaned using solid phase extraction, and analyzed by gas chromatography as a trimethylsilyl-derivative. The detection limit of the method was 5ngl^–1 (signal to noise ratio 4:1) which corresponds to ca. 15ng prehelminthosporol per mg dry weight of mycelium or 15ng prehelminthosporol per ml culture filtrate. The total amount of prehelminthosporol (mycelium plus culture filtrate) increased with cultivation time when examined in six isolates of B. sorokiniana after 6, 9, 12 and 15 days of incubation. The screening experiment of 17 isolates for prehelminthosporol production after 8 days of incubation revealed significant differences in the toxin production between the isolates. The isolates with low toxin production had lower virulence towards barley roots compared to those with higher production of the toxin. However, the virulence did not increase with prehelminthosporol level among the high producing isolates. Prehelminthosporol was also analyzed in a number of related Bipolaris and Drechslera species. In addition to B. sorokiniana, three out of six Bipolaris species (B. setariae, B. zeicola, B. victoriae) produced prehelminthosporol, which indicates that ability to produce prehelminthosporol is conserved among closely-related Bipolaris species.     

Effect of botanical insecticides and bacterial toxins on the gut enzyme of the rice leaffolderCnaphalocrocis medinalis

The effect of botanical insecticides and bacterial toxins on gut enzyme activity of larvae of the rice leaffolderCnaphalocrocis medinalis (Guenée) (Insecta: Lepidoptera: Pyralidae) was investigated. Gut enzyme activities were affected by botanical insecticides and bacterial toxin individually and in combination. When fed a diet of rice leaves treated with botanical insecticides and bacterial toxins, in bioassays the activities of gut tissue enzymes — acid phosphatases (ACP), alkaline phosphatases (ALP) and adenosine triphosphatases (ATPase) — of rice leaffolder larvae were affected. When combined, the effect was more severe at a low concentration. Larvae that were chronically exposed to botanical insecticides and bacterial toxins showed a reduction in weight (59–89%) and exhibited a significant reduction in ACP, ALP and ATPase activities. The combination ofBacillus thuringiensis kurstaki and botanical insecticides caused a decrease of twofold in enzyme activity even at reduced concentration. A synergistic effect was found when botanical insecticides and bacterial toxins were combined at low doses. These effects were most pronounced in early instars. Clear dose-response relationships were established with respect to enzyme activity. In conclusion: (i) biopesticides are relatively safe and biodegradable; (ii) a synergistic effect of botanical insecticides and bacterial toxins was found; (iii) less expensive, readily available and naturally occurring biopesticides could be an alternative for organic and inorganic pesticides in controlling RLF. http://www.phytoparasitica.org posting Sept. 28, 2004.