scholarly journals Types and composition of diseases and pests of restructured forest and pasture plants in the dry part of the Aral Sea

2021 ◽  
Vol 939 (1) ◽  
pp. 012084
Author(s):  
O Khujaev ◽  
D Obidjanov ◽  
O Tursunov ◽  
O Nazarova

Abstract Studies on the dried bottom of the Aral Sea have shown that dominant disease from 3 species of them in Haloxylon plant is Podosphaera leucotricha and the dominant species from 34 species of pests is Big Dwarf Haloxylon Locust (D. albidula) and Small Haloxylon Locust (D. annulata roseipen). Chemical and biological control measures were taken against this disease and pests. When using anti-inflammatory drugs Redomil gold, Dnox, Fundazol and Sporagin, their effectiveness is as follows: Redomil gold - 68% sp (2.0–2.5 kg / ha), Fundazol -50% ke (2.0 l / ha), Dnox - 40% ke (2.0 l / ha) and Sporagin (4.0, l / ha) were tested using fungicides in the norms. Of the drugs used in the experimental variant, Redomil gold, 68% s.p. (2.0-2.5 kg / ha) was the highest biological efficacy against powdery mildew in the variant in which the fungicides were applied, was 91.3%.

Author(s):  
I. J. Holb

Apple powdery mildew (Podoshphaera leucorticha) occurs wherever apples are grown. One of the most important fungal disease of apple which causing severe econimic loss on susceptible apple cultivars. This review focuses on the control of apple powdery mildew. The first part of the study provides details of novel aspects of non-chemical control approaches, including agronomic measures, mechanical and biological control options as well as essential features of apple cultivar resistance. After this, developments in chemical control options are described sperately for integrated and organic apple orchards.


Author(s):  
Sean D. Moore

Thaumatotibia leucotreta, known as the false codling moth, is a pest of citrus and other crops in sub-Saharan Africa. As it is endemic to this region and as South Africa exports most of its citrus around the world, T. leucotreta has phytosanitary status for most markets. This means that there is zero tolerance for any infestation with live larvae in the market. Consequently, control measures prior to exporting must be exemplary. Certain markets require a standalone postharvest disinfestation treatment for T. leucotreta. However, the European Union accepts a systems approach, consisting of three measures and numerous components within these measures. Although effective preharvest control measures are important under all circumstances, they are most critical where a standalone postharvest disinfestation treatment is not applied, such as within a systems approach. Conventional wisdom may lead a belief that effective chemical control tools are imperative to achieve this end. However, we demonstrate that it is possible to effectively control T. leucotreta to a level acceptable for a phytosanitary market, using only biological control tools. This includes parasitoids, predators, microbial control, semiochemicals, and sterile insects. Simultaneously, on-farm and environmental safety is improved and compliance with the increasing stringency of chemical residue requirements imposed by markets is achieved.


2020 ◽  
Vol 5 (1) ◽  
pp. 404-440 ◽  
Author(s):  
Mehrdad Alizadeh ◽  
Yalda Vasebi ◽  
Naser Safaie

AbstractThe purpose of this article was to give a comprehensive review of the published research works on biological control of different fungal, bacterial, and nematode plant diseases in Iran from 1992 to 2018. Plant pathogens cause economical loss in many agricultural products in Iran. In an attempt to prevent these serious losses, chemical control measures have usually been applied to reduce diseases in farms, gardens, and greenhouses. In recent decades, using the biological control against plant diseases has been considered as a beneficial and alternative method to chemical control due to its potential in integrated plant disease management as well as the increasing yield in an eco-friendly manner. Based on the reported studies, various species of Trichoderma, Pseudomonas, and Bacillus were the most common biocontrol agents with the ability to control the wide range of plant pathogens in Iran from lab to the greenhouse and field conditions.


2021 ◽  
Author(s):  
Sarah E. Thomas ◽  
Julissa Rojas-Sandoval ◽  
Pedro Acevedo-Rodríguez

Abstract L. camara is a highly variable ornamental shrub, native of the neotropics. It has been introduced to most of the tropics and subtropics as a hedge plant and has since been reported as extremely weedy and invasive in many countries. It is generally deleterious to biodiversity and has been reported as an agricultural weed resulting in large economic losses in a number of countries. In addition to this, it increases the risk of fire, is poisonous to livestock and is a host for numerous pests and diseases. L. camara is difficult to control. In Australia, India and South Africa aggressive measures to eradicate L. camara over the last two centuries have been largely unsuccessful, and the invasion trajectory has continued upwards despite control measures. This species has been the target of biological control programmes for over a century, with successful control only being reported in a few instances.


Author(s):  
J. N. Kapoor

Abstract A description is provided for Podosphaera leucotricha. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Malus spp., chiefly on M. pumila (apple), peach (Prunus persica), quince (Cydonia ualgaris) and Photinia spp. also attacked (Hirata, 1966). Also reported on almond fruit (43, 2544). DISEASE: Powdery mildew of apple. GEOGRAPHICAL DISTRIBUTION: Africa (? Kenya, Rhodaia, South Africa, Tanzania); Asia (China, India, Israel, Japan, U.S.S.R.); Australia and New Zealand, Europe (widely distributed) North America (Canada and U.S.A.); South America (Argentina, Brazil, Chile, Colombia, Peru). (CMI map 118). TRANSMISSION: Overwinters on host as dormant mycdium in blossom buds. The role of deistothecia in overwintering is doubtful. Spread by wind-borne conidia (Anderson, 1956).


2011 ◽  
Vol 50 (No. 2) ◽  
pp. 65-69 ◽  
Author(s):  
J. Blažek

Incidences of powdery mildew were repeatedly evaluated for two years on 1 420 young seedlings of 20 progenies (of different levels of mildew susceptibility) in a green house, and then for 10 years on 642 seedlings in an orchard. Part of the seedlings in the orchard were pre-selected for the characteristic and others not. Except for the first scoring done in the first year, there was no correlation between mildew incidence on individual seedlings in the green house and their mean performance in the orchard. The seedlings with scores above 6 (resistant or tolerant) at the first stage of evaluation in the green house, however, yielded four times more desirable seedlings after final selection in the orchard than the mean of the total. The progenies that had a better healthy state as a whole yielded more partially resistant genotypes than those with low mean scores. Therefore, the progenies that most rapidly develop infestation on the whole lot should be discarded, whereas those that retain a healthy state longer should be subjected to individual selection according to the previous item.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4534 ◽  
Author(s):  
Chi Zeng ◽  
Lingbing Wu ◽  
Yao Zhao ◽  
Yueli Yun ◽  
Yu Peng

Background Tea is one of the most economically important crops in China. However, the tea geometrid (Ectropis obliqua), a serious leaf-feeding pest, causes significant damage to tea crops and reduces tea yield and quality. Spiders are the most dominant predatory enemies in the tea plantation ecosystem, which makes them potentially useful biological control agents of E. obliqua. These highlight the need for alternative pest control measures. Our previous studies have shown that tea saponin (TS) exerts insecticidal activity against lepidopteran pests. Here, we investigate whether TS represents a potentially new alternative insecticide with no harm to spiders. Methods We investigated laboratory bioactivities and the field control properties of TS solution against E. obliqua. (i) A leaf-dip bioassay was used to evaluate the toxicity of TS to 3rd-instar E. obliqua larvae and effects of TS on the activities of enzymes glutathione-S-transferase (GST), acetylcholinesterase (AChE), carboxylesterase (CES) and peroxidase (POD) of 3rd-instar E. obliqua larvae in the laboratory. (ii) Topical application was used to measure the toxicity of 30% TS (w/v) and two chemical insecticides (10% bifenthrin EC and 50% diafenthiuron SC) to two species of spider, Ebrechtella tricuspidata and Evarcha albaria. (iii) Field trials were used to investigate the controlling efficacy of 30% TS against E. obliqua larvae and to classify the effect of TS to spiders in the tea plantation. Results The toxicity of TS to 3rd-instar E. obliqua larvae occurred in a dose-dependent manner and the LC50 was 164.32 mg/mL. Activities of the detoxifying-related enzymes, GST and POD, increased in 3rd-instar E. obliqua larvae, whereas AChE and CES were inhibited with time by treatment with TS. Mortalities of E. tricuspidata and E. albaria after 48 h with 30% TS treatment (16.67% and 20%, respectively) were significantly lower than those with 10% bifenthrin EC (80% and 73.33%, respectively) and 50% diafenthiuron EC (43.33% and 36.67%, respectively). The highest controlling efficacy of 30% TS was 77.02% at 5 d after treatment, which showed no difference to 10% bifenthrin EC or 50% diafenthiuron SC. 30% TS was placed in the class N (harmless or slightly harmful) of IOBC (International Organization of Biological Control) categories for natural enemies, namely spiders. Conclusions Our results indicate that TS is a botanical insecticide that has a good controlling efficacy in E. obliqua larvae, which suggests it has promise as application in the integrated pest management (IPM) envisaged for tea crops.


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