Exotic Virus and Virus-like Diseases of Fruit Trees1

According to the results of enquiries by the ISHS Working Group on fruit-tree virus diseases, about 40 of these could be considered as exotic for the EPPO area. In fact, most are probably due to the same pathogens and no more than 12 exotic diseases of some economic importance exist. Those which are described here are, with a few exceptions, those reported in the EPPO Al list and in the EEC directives. Some are associated with mycoplasma-like organisms (X disease, peach rosette, peach yellows, little peach), others with rickettsia-like bacteria (peach phony, plum leaf scald), others with viruses (peach yellow bud mosaic, prunus stem pitting, apple union necrosis, cherry rasp leaf, flat apple, plum line pattern) and some, at last, are of unknown origin (peach mosaic). Most of these diseases show a natural spread, are able to infect many different species and would find, in the EPPO area, favourable conditions to settle and spread. Avoiding introduction of exotic diseases requires that the fruit-tree growing countries, and especially those which have recently developed their fruit-tree industry, should complete an inventory of the viruses present. ISHS has been struggling over recent years to standardize indexing methods and to arrive at better and more uniform international virus testing. The tremendous progress recently observed in the field of indexing now allows a contamination to be detected within weeks or even hours and consequently should help avoid or limit the introduction of new pathogens.     

Certification Schemes and their Benefit to Plant Protection1

In Israel, compulsory certification schemes have been of major importance in the protection of many crops. The examples discussed include carnation, rose, grapevine and avocado. Citrus certification in particular has provided an essential back-up to the programme of eradication of citrus tristeza virus. New meristem-culture techniques and virus-testing methods will make such schemes easier to develop in future and open possibilities for internationally accepted schemes.     

果树对水分胁迫的反应与适应

从形态解剖和生理生化方面综述了果树对水分胁迫的反应和适应性。     

荒漠区珍稀和野生果树的引种驯化

能在热带荒漠地区进行商业化栽培的作物种类是有限的,园艺作物尤其如是。本研究的目的就是通过引种驯化为热带荒漠区开发新品种。我们以下述两个来源的多年生植物为基础:干旱区和半干旱区人民食用的有营养价值的水果或干果的野生植物种;第二是从当地市场或栽培者那里能收集到的珍稀种类。以色列的内盖夫荒漠气候条件变幅宽广,水土类型多样,是本项研究的理想地点。本研究利用内盖夫的异质特点对向荒漠区引种驯化的不少植物的适宜性进行了预选试验。本文总结了从1984年开始的4年工作,并叙述了总的进展,详细介绍了六种预选植物。     

Maize Virus and Mycoplasma Diseases in Peru

Abstract

Surveys of maize for virus and mycoplasma-like diseases were conducted in Peru in 1978 and 1980. The following pathogens were discovered and identified: aphid-borne maize dwarf mosaic virus, beetle-borne maize chlorotic mottle virus, Peregrinus maidis-borne maize mosaic and maize stripe viruses, and Dalbulus maidis-borne maize rayado fino virus, corn stunt spiroplasma (CSS) and maize bushy stunt mycoplasma (MBSM). Some of these insect-borne pathogens are important constraints to maize production in Peru. Maize chlorotic mottle in the department of Lima and Cajamarca and ‘puca poncho’, a disease caused by CSS and/or MBSM, in Ayacucho significantly limit maize yields. As a result of these surveys, we believe that the principal maize virus and mycoplasma-like diseases in Peru have been identified, an accomplishment unrealised in other Latin American countries at present.     

PM 4/10(2): Certification scheme for Rubus

Specific scope

This standard describes the production of certified pathogen‐tested material of Rubus.

Specific approval and amendment

First approved in 2004–09. Revised in 2009–09.

     

PM 4/16(2): Certification scheme for hop

Specific scope

This standard describes the production of certified pathogen‐tested material of hop.

Specific approval and amendment

First approved in 1996–09. Revised in 2009–09.

     

Diversity of Phytoplasmas Infecting Fruit Trees and Their Vectors in Croatia

Journal of Plant Diseases and Protection - A survey started in 2002 (Križanac et al. 2008) was continued to determine the diversity of phytoplasmas infecting fruit trees and their vectors in...     

山东苹果主要病虫害化学防治技术

山东省苹果园害虫优势种群是蚜虫、桃小食心虫、苹小卷、金纹细蛾、害螨等 ;病害主要是斑点落叶病、轮纹病。根据不同病虫害的发生发展规律和烟台农科院多年来的化学防治试验研究 ,明确了不同苹果品种上适用的有效药剂和不同药剂的杀虫 (菌 )谱、用药适期、施药方法 ,制定了相应的防治策略 ,提出了合理用药、交替施药和安全喷药等诸多注意事项     

Enhancement of Postharvest Disease Resistance in Ya Li Pear (Pyrus bretschneideri) Fruit by Salicylic Acid Sprays on the Trees during Fruit Growth

The Ya Li pear (Pyrus bretschneideri) trees were sprayed three times with 2.5 mM salicylic acid (SA) around 30, 60 and 90 days after full flowering. The fruit were harvested at commercial maturity (about 120 days after full flowering), inoculated with Penicillium expansum, and incubated at 20 °C, 95–100% RH. The results showed that resistance to the pathogen of the mature pear fruit was remarkably enhanced by the SA sprays. Disease incidence in the SA-treated fruit was 58.0% or 26.5%, and lesion diameter on SA-treated fruit was 58.4% or 29.0% lower than that in/on fruit without SA treatment (control) on day 12 or 17 after incubation, respectively. The SA spray applied to the trees around 30 days after full flowering notably enhanced accumulation of hydrogen peroxide in the young fruit. Meanwhile, activities of defense enzymes, including peroxidase, phenylalanine ammonia-lyase (PAL), chitinase or β-1,3-glucanase in the young fruit from SA-treated trees was 29.5%, 60.0%, 24.4% or 35.7% higher than that in the control fruit 4 days after the SA spraying. Furthermore, after harvest, activities of PAL, chitinase and β-1,3-glucanase were still significantly higher in the mature pear fruit from the trees sprayed three times with SA than those of the control fruit. Activities of the antioxidant enzymes including catalase and ascorbate peroxidase in the young fruit were significantly reduced by SA spraying. However, the activity of another antioxidant enzyme, glutathione reductase in the young fruit was significantly enhanced by SA spraying. These results suggest that enzymes exerting their functions in different ways may be coordinately regulated by SA in the pear fruit. Our study indicates that treatment of SA sprays on the trees may provide further protection against postharvest disease of Ya Li pear fruit in practice and could be used as an alternative and economical approach to reduce application of chemical fungicides.     

Wheat Diseases in Turkey1

Cereal crop production is one of the most important projects in the agricultural improvement programme for Turkey. Overall, wheat represents 61 % of the cereal crop. While wheat production was almost 4 million tons in 1950, this reached a limit of 10 million tons in 1970. A number of diseases continue to afflict the crop from time to time, causing heavy losses. The most important of these are: bunt ( Tilletia foetida and T. caries ), loose smut ( Ustilago nuda ), rusts ( Puccinia strilformis, P. graminis f. sp. tritici, P. recondita f. sp. tritici ), leaf blotch ( Septoria tritici ), root and foot rots ( Fusarium spp., Drechslera sorokiniana, Pseudocercosporella herpotrichoides, Alternarla alternate, Sclerotium spp. and Rhizoctonia spp.). The diseases appear all over the country. Average losses due to rusts in epidemics are estimated at about 30–35 % in the whole country. Annual losses from covered smut are about 15–20 %, and from loose smut from 0.1 % to almost 20 % depending on the weather conditions of the year, on variety and on locality. Root rots have gained importance in some places, especially in Thrace in the last few years. In addition to the above diseases, several others occur occasionally but are of minor importance: powdery mildew ( Erysiphe graminis f. sp. tritici ), dwarf smut ( Tilletia contraversa ), flag smut ( Urocystis tritici ), take-all ( Gaeumannomyces graminis ) and a wheat mosaic virus (recently observed in a province of Central Anatolia).     

Mosaic Virus and Leaf Curl Diseases of Okra in Nigeria

Abstract

The etiology and incidence of okra leaf curl and okra mosaic virus diseases observed in Nigeria are reviewed and the difficulty in evolving a control measure for these two diseases is discussed.     

高粱病毒病的病原及防治对策

高粱病毒病此前未见报道，症状易与高粱炭疽病、大斑病混淆。电子显微镜检测，高粱病毒病由 多种植物病毒复合侵染所致。影响此病的因素有栽培条件、生育期和传毒介体昆虫。提出"以栽培管理为 基础，消灭传毒媒介为重点.辅以药剂防治"的综合防治对策。     

中国伊犁野生果树及近缘种研究

中国伊犁河谷地野果林由新疆野苹果(Malus sieversii (Ldb.) M. Roem.)、野杏(Armeniaca vulgaris Lam.)、野生樱桃李(Prunus divaricata Ldb.)、野生欧洲李(P.domestica L.)和野核桃(Juglans regia L.)等组成.它们的存在是独特的生境条件综合作用的结果.它们分布于天山山区环境最优越的地段,是我国特殊的温带落叶阔叶林森林生态系统类型,也是我国面积大、种类组成丰富的原始野生果树林.其野生果树种质资源十分丰富,现已查明的野生果树及近缘种9科21属58种,是多种温带落叶果树栽培种的重要起源地之一.     

崇阳县几种水稻病毒病的调查分析

崇阳县近年水稻病毒病发生呈流行爆发态势,通过田间调查和资料比对,发生的水稻病毒病主要包括水稻普通矮缩病、水稻黄叶病、水稻黄萎病、水稻齿矮缩病、水稻黑条矮缩病、南方水稻黑条矮缩病等,并且多病混发情况比较普遍,不同水稻品种发病程度不同,中晚稻普遍重于早稻,零星种植水稻田重于集中种植.选用抗病品种连片种植、重点防治稻飞虱叶蝉...     

San José Scale in Deciduous Fruit Orchards of Some European Countries (Survey of Scale Insect Infestations in European Orchards No. IV)

Fruit tree branch and bark samples have been collected from several European countries (Czechoslovakia, Greece, Hungary, Poland, Turkey, European part of USSR) from apple, pear, peach, plum, cherry and sour cherry. Twenty-five scale insect species were found in the samples. Distribution maps of Quadra & pidiotus perniciosus on different fruit species are given. No significant changes in the distribution of this species in Central Europe can be observed in the last 30 years. Q. perniciosus is present in higher density on apple wherever it occurs, and is less frequent on pears and plums. It is frequent on peach and sometimes on cherry, but generally at low densities. It is rare on sour cherry.