Agriculture Reference
In-Depth Information
in response to field applications of vermicomposts. Such reports, although not numerous, provide
an adequate basis to justify further research into this subject. Greenhouse experiments at OSU have
demonstrated significant suppression of populations of aphids ( Myzus persicae ), mealy bugs
( Pseudococcus ), and caterpillars ( Pieris brassicae ) by substituting low rates of vermicomposts into
a soilless plant growth medium (Metro-Mix 360) for tomatoes, peppers, and cabbages (Arancon
et al. 2004d).
The possible mechanisms of arthropod pest suppression by organic matter, composts, and
vermicomposts are still speculative, but changes in the nutrient characteristics and balances of
plants in response to vermicomposts compared with inorganic fertilizers and possibly the phenol
contents of plant leaves have been suggested mechanisms because organic nitrogen is released
more slowly from organic amendments such as vermicomposts than from inorganic fertilizers. This
would make plants less acceptable to arthropod attacks (Patriquin et al. 1995).
P LANT -P ARASITIC N EMATODES
There is very extensive scientific literature demonstrating that additions of organic matter to soils
may sometimes decrease populations of plant-parasitic nematodes appreciably (Addabdo 1995).
Akhtar (2000) reviewed 212 scientific papers that discussed the effects of various organic amend-
ments including composts (Chen and Zuckerman 2000; Gupta and Kamar 1997; McSorley and
Gallaher 1995; Miller 2001; Zambolin et al. 1996) on plant-parasitic nematode populations.
There have been a few reports in the scientific literature of vermicomposts suppressing
populations of plant-parasitic nematodes. Swathi et al. (1998) demonstrated that 1.0 kg m −2 of
vermicompost suppressed attacks of Meloidogyne incognita in tobacco plants. Morra et al. (1998)
reported partial control of Meloidogyne incognita by vermicompost amendments to soils in a
tomato-zucchini rotation. Ribeiro et al. (1998) reported that vermicomposts decreased the num-
bers of galls and egg masses of Meloidogyne javanica . Arancon et al. (2002, 2004e) reported
significant suppression of plant-parasitic nematodes by field applications of vermicomposts,
ranging from 2 to 8 kg/ha, applied to tomato (Figure 18.7), pepper, strawberry, and grape crops
( Figure 18.8 ). Suppression of plant-parasitic nematodes by field applications of paper waste,
food waste, and cattle manure vermicomposts was also reported by the same group of workers
at OSU (Arancon et al. 2002, 2004e).
There are a number of possible mechanisms that may explain decreases in populations of plant-
parasitic nematodes by vermicomposts. Predatory-prey interactions, which decrease populations of
plant-parasitic nematodes, may also provide one feasible explanation of the mechanism. For
16
14
12
10
8
6
4
2
0
Inorganic
fertilizer
Paper
waste
20 t/ha
Paper
waste
10 t/ha
Cattle
manure
20 t/ha
Cattle
waste
10 t/ha
Food
waste
20 t/ha
Food
waste
10 t/ha
Compost
20 t/ha
FIGURE 18.7 Plant-parasitic nematodes (mean ° SE) in field soils planted with tomatoes and amended with
vermicomposts.
 
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