Deleterious activity of cultivated grasses (Poaceae) and residues on soilborne fungal, nematode and weed pests

Abstract

Experiments were conducted in laboratory bioreactors and in field plots to test effects of certain cultivated members of the grass family (Poaceae = Gramineae), including wheat (Triticum aestivum cv. Yolo), barley (Hordeum vulgare cv. UC337), oats (Avena sativa cv. Montezuma), triticale (X Triticosecale), and a sorghum-sudangrass hybrid (Sorghum bicolor x S. sudanense = "sudex", cv. Green Grazer V) for soil disinfestation potential. Soilborne pest organisms tested for effects on survival and activity included the phytopathogens Sclerotium rolfsii, Pythium ultimum and Meloidogyne incognita, and a variety of weed taxa. Following soil amendment, bioreactors were incubated for 7 days at ambient (23°C) or elevated, but sublethal (38°C day/27°C night), soil heating regimens. Addition of each of the poaceous amendments to soil at 23°C resulted in inconsistently reduced tomato root galling (49-97%) by M. incognita, or reduced recovery of S. rolfsii and P. ultimum (0-100%) fungi in soil, after 7 days' incubation (P ≤ 0.05). When the organisms were exposed to the poaceous soil amendments at the 38 o / 27 o temperature regimen, nematode galling and recovery of active fungi were consistently and significantly reduced by 98-100%. These results demonstrated feasibility of soil disinfestation ("biofumigation") by activity of poaceous amendments, further aided by combining plant residues with soil heating (e.g. solarization). Results from three field experiments with sudex cover crops, conducted throughout the growing season, demonstrated biocidal activity on a range of weedy plants, including Amaranthus retroflexus, Calandrinia ciliata, Cerastium arvense, Digitaria sanguinalis, Echinochloa crus-galli and Poa annua. Both shoots and roots of sudex provided allelopathic weed biomass reductions of 35-100%, and for at least 106 days after shredding. Deleterious activity of shredded residues incorporated in soil was less persistent. These properties in poaceous crops can be useful for soil disinfestation;

Weed seed inactivation in soil mesocosms via biosolarization with mature compost and tomato processing waste amendments

“…Biosolarization research has explored the use of a number of organic matter amendments in the soil to control a variety of pests, including nematodes, fungi, bacteria and weeds. Soil amendments such as fresh sheep manure, Japanese radish residues, mixtures of sheep and chicken manure, Brassica crop residues and pellets , sugar beet vinasse and olive pomace, have been tested and reported to be effective for biosolarization . While these studies have provided information regarding the end result of biosolarization, less is known regarding biological, chemical and physical conditions in the soil during biosolarization and how they relate to pest inactivation kinetics during treatment.…”

Assessment of tomato and wine processing solid wastes as soil amendments for biosolarization

“…Additionally, some organic matter sources have already been shown to be compatible with biosolarization, such as chicken manure (López-Pérez et al, 2005), cruciferous, alliaceous, and poaceous crop residues (Gamliel and Stapleton, 1993a;Mallek et al, 2007;Stapleton et al, 2010), wheat bran (Simmons et al, 2014), and others. However, these amendments represent only a narrow fraction of the potential organic matter sources that might be used for biosolarization.…”

Evaluation of Cool-season Vegetable Rotations in Organic Production

“…Sunn hemp and southernpea used as a summer rotation in Florida tomato plots were found to suppress plant pathogenic nematodes while enhancing beneficial nematodes (Wang et al, 2002). In a controlled experiment, preplant incorporation of wheat (Triticum aestivum) residues significantly reduced RKN galling on tomato roots and completely inhibited germination of S. rolfsii sclerotia at soil temperatures of 23°C (Stapleton et al, 2010).…”