The predaceous activity of nematode‐trapping fungi added to soil
TL;DR: Evidence suggests that fungi forming the constricting ring type of trap are more efficient in reducing soil nematode populations than fungi forming adhesive reticulate traps.
Abstract: SUMMARY
Predaceous activity of different species of nematode-trapping fungi introduced into non-sterile soil varies in both intensity and duration. In some cases free-living nematode populations increase after the addition of mycelium of these fungi to the soil and in other cases decrease.
Evidence suggests that fungi forming the constricting ring type of trap are more efficient in reducing soil nematode populations than fungi forming adhesive reticulate traps,
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TL;DR: This chapter discusses the mechanisms of control by Crop Rotation and the principles of plant disease control as well as specific diseases caused by fungus and bacteria.
Abstract: Introduction .................................................................................................................................................................. 413 General Principles of Plant Disease Control ........................................................................... 414 Control of Specific Diseases ........................................................................................................................ 416 Diseases Caused by Fungi ............................................................................................................... 416 Diseases Caused by Bacteria ......................................................................................................... 435 Diseases Caused by Nematodes ................................................................................................... 438 Virus Diseases ................................................................................................................................................ 443 Parasitle Seed Plants .............................................................................................................................. 446 Mechanisms of Control By Crop Rotation .................................................................................... 4 4 6
124 citations
TL;DR: ( I )
Abstract: ( I ) Endoparasites . 247 ( a ) Encysting spores . 247 (b) Adhesive conidia . . . . . . . . . . . . 248 (c) Ingested conidia . 249 (2) Predators . . . . . . . . . . . . . . . 249 ( a ) Unmodified adhesive hyphae . . . . . . . . . . 252 (b) Adhesive branches . . . . . . . . . . . . 252 (c) Adhesive nets . . . . . . . . . . . . . 253 ( d ) Adhesive knobs . . . . . . . . . . . . . 253 (e) Non-constricting rings . . . . . . . . . . . 254 (f) Constricting rings . . . . . . . . . . . . 255 I11 . Identification . . . . . . . . . . . . . . . 256 ( I ) Taxonomy . . . . . . . . . . . . . . 256 . . . . . . . . . . . . . . . . . . . . . . . .
111 citations
TL;DR: It appears that the development of predaceous efficiency has been accompanied by a tendency to lose those characters associated with an efficient saprophytic existence in the soil; namely rapid growth rate and good competitive sa Prophytic ability.
Abstract: SUMMARY
A study of thirteen species of nematode-trapping Hyphomycetes demonstrated wide differences in their growth rate, competitive saprophytic ability, effect on free-living nematode populations and ability to produce traps spontaneously.
The species producing adhesive reticulate traps tended to have the most rapid growth rates and the highest saprophytic ability ratings. In the soil they appeared to be pre-daceously inefficient and did not form traps in pure culture. In contrast the ring-formers had slow growth rates and lower saprophytic ability ratings. They tended to be predaceously efficient and two of the four species studied formed traps spontaneously. The adhesive branch or knob-forming fungi resembled the ring-formers in their growth rates, predaceous efficiency and spontaneous trap formation.
Thus it appears that the development of predaceous efficiency has been accompanied by a tendency to lose those characters associated with an efficient saprophytic existence in the soil; namely rapid growth rate and good competitive saprophytic ability.
90 citations
TL;DR: The chapter discusses physiological, biochemical, and ultrastructural aspects of both predatory and endoparasitic nematophagous fungi and explains current views on the role of the fungi in natural ecosystems.
Abstract: Publisher Summary The chapter discusses physiological, biochemical, and ultrastructural aspects of both predatory and endoparasitic nematophagous fungi and explains current views on the role of the fungi in natural ecosystems. Both predatory and endoparasitic fungi share the property of producing sophisticated morphological structures that enable them to attack living nematodes. Some predatory fungi form trapping structures only after induction by external stimuli (e.g. the presence of living nematodes), others develop traps spontaneously. Parasites of nematodes are found among all major fungal taxonomic groups. All devices that mediate fungal-nematode interactions are either specialized hyphal structures or differentiated cells—for example, conidia. These “special-purpose” structures are equipped to establish a firm contact with the prey and, subsequently, to mediate penetration of the cuticle. The various morphological adaptations employed in nematode-capturing are described. The complex nematode-fungus interaction is mainly descriptive in nature and is primarily based on various light- and electronmicroscopical methods as major tools. Light microscopy and video-enhanced contrast microscopy have been used to study interactions at the cellular level using living organisms, and have proved especially useful to investigate kinetics of the infection process.
84 citations
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TL;DR: Methods used in the study of predacious fungi include techniques for obtaining mixed cultures of the fungi from Nature, for isolating those that will grow in pure culture, for observing living material and for making permanent microscopical preparations.
Abstract: Methods used in the study of predacious fungi include techniques for obtaining mixed cultures of the fungi from Nature, for isolating those that will grow in pure culture, for observing living material and for making permanent microscopical preparations.
143 citations
Journal Article•
35 citations
TL;DR: The results obtained strongly suggest that under laboratory conditions and in pot cultures congenial conditions for growth in soil of the predacious fungi can be produced but that, in the field, only sparse growth of these mushrooms can be obtained, insufficient to affect eelworm attacks.
Abstract: SUMMARY
Laboratory and pot experiments by various workers up to 1956 suggested that the effects of eelworm attack on certain crops could be partly overcome by inoculating eelworm-infested soil with the mycelium of predacious fungi.
The present paper demonstrates some of the factors operative in soil which affect the ‘predacity’ of some of these fungi.
The results obtained strongly suggest that under laboratory conditions and in pot cultures congenial conditions for growth in soil of the predacious fungi can be produced but that, in the field, only sparse growth of these fungi can be obtained, insufficient to affect eelworm attacks.
The use of farmyard or green manure has consistently given better crops in eelworm-infested soils irrespective of whether predacious fungi were naturally present 01 added.
28 citations
TL;DR: A method has been developed to obtain direct evidence of the effects of treatments on the predaceous activity of indigenous populations of nematode-trapping fungi in the soil, such work being regarded as fundamental to the investigation of methods using these fungi as agents of biological control.
Abstract: ATTEMPTS at the biological control of soil-borne eelworm pests have usually involved a process of green manuring or the addition of some organic amendment to the soil1–3. A method has been developed to obtain direct evidence of the effects of such treatments on the predaceous activity of indigenous populations of nematode-trapping fungi in the soil, such work being regarded as fundamental to the investigation of methods using these fungi as agents of biological control.
19 citations
TL;DR: A microplot experiment was made to test the effect of a predacious fungus and three types of organic matter upon potato root eelworm and the treatments were without effect upon the yield of potatoes or upon the final cyst and egg populations.
Abstract: A microplot experiment was made to test the effect of a predacious fungus (Dactylaria thaumasia Drechsler) and three types of organic matter (leaf mould, compost and chopped cabbage) upon potato root eelworm (Heterodera rostochiensis Woll.). The initial population of the eelworm was low and the treatments were without effect upon the yield of potatoes or upon the final cyst and egg populations.
18 citations