scholarly journals Biological Control of Lettuce Drop and Host Plant Colonization by Rhizospheric and Endophytic Streptomycetes

2016 ◽  
Vol 7 ◽  
Author(s):  
Xiaoyulong Chen ◽  
Cristina Pizzatti ◽  
Maria Bonaldi ◽  
Marco Saracchi ◽  
Armin Erlacher ◽  
...  
1995 ◽  
Vol 73 (S1) ◽  
pp. 1275-1283 ◽  
Author(s):  
Shigehito Takenaka

To develop efficient control measures against fungal plant pathogens, the dynamics of host plant colonization during disease development and the interactions among fungi within host plant tissues need to be clarified. These studies require accurate quantitative estimation of specific fungal biomass in plant tissues. This has been approached by direct-microscopic methods, cultural methods, chemical determinations of fungal components, serological methods, and molecular methods. Among these methods, serological and molecular methods provide rapid, specific, and sensitive quantitative measures of fungal biomass in host plant tissues. Therefore, studies on fungal dynamics of host plant colonization using these two methods are presented. Some examples of species interactions among pathogenic fungi within host plants, such as synergism and competition, are reviewed and the usefulness of serological and molecular methods for studies on these interactions is presented. These quantitative methods will provide helpful information for understanding the ecology of plant pathogenic fungi, such as the dynamics of host plant colonization and species interactions. Key words: quantitative methods, fungal biomass, ELISA, PCR, fungal colonization, species interaction.


2019 ◽  
Vol 112 (4) ◽  
pp. 1587-1597 ◽  
Author(s):  
Juan Pedro Raul Bouvet ◽  
Alberto Urbaneja ◽  
César Monzó

Abstract The Spirea citrus aphid, Aphis spiraecola Patch, and the cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), are key pests of clementine mandarines in the Mediterranean basin. Severity of aphid infestations is determined by environmental variables, host plant phenology patterns, and the biological control exerted by their associated natural enemies. However, there is no information about the role these limiting and regulating factors play. Aphid densities, citrus phenology, and associated predators that overwinter in the crop were monitored weekly throughout two flush growth periods (February to July) in four clementine mandarin groves; relationships between these parameters and environmental variables (temperature and precipitation) were studied. Our results show exponential increase in aphid infestation levels to coincide with citrus phenological stages B3 and B4; shoots offer more space and nutritional resources for colony growth at these stages. Duration of these phenological stages, which was mediated by mean temperature, seems to importantly determine the severity of aphid infestations in the groves. Among those studied, the micro-coccinellids, mostly Scymnus species, were the only group of predators with the ability to efficiently regulate aphid populations. These natural enemies had the highest temporal and spatial demographic stability. Aphid regulation success was only achieved through early presence of natural enemies in the grove, at the aphid colonization phase. Our results suggest that conservation strategies aimed at preserving and enhancing Scymnus sp. populations may make an important contribution to the future success of the biological control of these key citrus pests.


Zootaxa ◽  
2009 ◽  
Vol 1983 (1) ◽  
pp. 1-22 ◽  
Author(s):  
LAURENCE A. MOUND ◽  
DESLEY TREE

The Sericothripinae is a largely tropical group of about 140 species that are often strikingly bicoloured and have complex surface sculpture, but for which the biology is poorly known. Although 15 genera have been described in this subfamily, only three of these are currently recognised, with five new generic synonymies indicated here. In Australia, Sericothrips Haliday is introduced, with one European species deployed as a weed biological control agent. Hydatothrips Karny comprises 43 species worldwide, with six species found in Australia, of which two are shared with Southeast Asia, and four are associated with the native vine genus, Parsonsia. Neohydatothrips John comprises 96 species worldwide, with nine species in Australia, of which one is shared with Southeast Asia and two are presumably introduced from the Americas. Illustrated keys are provided to the three genera and 16 species from Australia, including six new species [Hydatothrips aliceae; H. bhattii; H. williamsi; Neohydatothrips barrowi, N. bellissi, N. katherinae]. One new specific synonym is recognised [Hydatothrips haschemi Girault (=H. palawanensis Kudo)], also four new generic synonyms [Neohydatothrips John (=Faureana Bhatti; Onihothrips Bhatti; Sariathrips Bhatti; Papiliothrips Bhatti); Sericothrips Haliday (=Susserico- thrips Han)].


2018 ◽  
Vol 44 (2) ◽  
pp. 137-142 ◽  
Author(s):  
Micaele Aparecida Franco da Silva ◽  
Karina Elaine de Moura ◽  
Kamila Ellen de Moura ◽  
Denise Salomão ◽  
Flávia Rodrigues Alves Patricio

ABSTRACT Lettuce drop, caused by Sclerotinia minor and S. sclerotiorum, is one of the most important diseases that affect lettuce crop in Brazil. In previous studies, isolates of Trichoderma asperellum (IBLF 897, IBLF 904 and IBLF 914) and T. asperelloides (IBLF 908) were selected for the biocontrol of this disease. In this subsequent study, the compatibility of these isolates with pesticides used in lettuce crop in Brazil was evaluated. Initially, the mycelial growth of isolates was evaluated in culture medium plus pesticides. Then, the effect of pesticides on the parasitism of T. asperelloides isolate IBLF 914 in baits and sclerotia of S. minor and S. sclerotiorum, as well as on the survival of lettuce seedlings, was evaluated in gerboxes after application on baits and sclerotia of the antagonist with pesticides at their respective commercial doses. The fungicides pencycuron and mandipropamid and the insecticide imidacloprid did not affect the mycelial growth of Trichoderma isolates. The fungicide iprodione did not affect the mycelial growth of T. asperellum isolates. but the isolate of T. asperelloides was sensitive from the concentration of 10 µg.L-1 fungicide. Procymidone reduced the mycelial growth of Trichoderma isolates from the concentration of 10 µg.L-1 fungicide, and azoxystrobin reduced the conidial germination of the isolates of the antagonist, showing LD50 between 0.36 and 0.42 µg.L-1 fungicide. On the other hand, in the experiment carried out in “gerboxes”, none of the pesticides reduced the parasitism of baits and sclerotia or reduced the control of S. minor and S. sclerotiorum in lettuce seedlings. Results indicate that the biological control of lettuce drop with T. asperelum isolate IBLF 914 can be compatible with the remaining phytosanitary treatments used in lettuce crop.


Zootaxa ◽  
2009 ◽  
Vol 2288 (1) ◽  
pp. 42-50 ◽  
Author(s):  
THOMAS D. EICHLIN ◽  
OONA S. DELGADO ◽  
LORRAINE W. STRATHIE ◽  
COSTAS ZACHARIADES ◽  
JOSE CLAVIJO

A new species of Sesiidae, Carmenta chromolaenae Eichlin, is described to make the name available to researchers evaluating the moth's potential for biological control of its host plant, Chromolaena odorata, in South Africa and other parts of the plant's invasive range. This clearwing moth species was reared from the host plant in Venezuela. The adult moth, including the male and female genitalia, larva, and pupa are described and illustrated. Its biology and possible use as a control agent are discussed.


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