Oct 12 - OCT 12 LECTURE NOTES nematodes as plant pathogens what is soil root systems general nematode information soybean cyst nematodes soybeans

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OCT 12 LECTURE NOTES: nematodes as plant pathogens what is soil? root systems general nematode information soybean cyst nematodes soybeans as a crop history of soybean cyst SCN life cycle brown spot: environment (extended monsoon season) citrus canker: pathogen (introduced strains), environment (hurricanes) coffee rust: host (monoculture), environment (reduced plant spacing) downy mildew: pathogen (introduced pathogen) fire blight: host (introduced susceptible hosts) late blight: host (uniformly susceptible), pathogen (introduced pathogen), environment (cool, wet weather) SALB: host (bred susceptible hosts, monoculture), environment (reduced plant spacing SCLB: host (introduced TMS cytoplasm), pathogen (development of race T), environment (wet weather) a major concern when using narrow spectrum, eradicant fungicides is that not all diseases will be controlled pathogens will develop resistance to the fungicide the fungicide will degrade too quickly in the environment the fungicide will affect non-target organisms all of the above answer: not all diseases will be controlled (though pathogens will develop resistance to the fungicide could be a decent answer) max amount of pesticide legally allowed on an agricultural product at the time of harvest is the LD50 no observable adverse effect level (NOAEL allowable day intake (ADI) tolerance none of the above answer: TOLERANCE pesticides would most likely be used on corn oats wheat apples
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soybeans answer: APPLES, because it is a high value crop that farmers want to protect the organization that oversees the registration of agricultural pesticides in the US is the USDA FDA ARS EPA all of the above answer: EPA (asked neighbor) soilborne pathogens fungi bacteria (viruses) nematodes (most asre soilborne) what is soil? soil is created over millions of years made from rock and organic matter erosion by wind, rain, ice, and changes in temperature decaying organic matter soil types size and proportion of mineral particles sand (large) silt (medium) clay (small) sand more air space, very quick water drainage clay less air space, difficult for water to drain agricultural soils best agricultural soils are looms mixture of mineral sizes mixture of sizes of air spaces half of the soil consists of air spaces balance of holding moisture and drainage organic matter helps retain moisture binds essential nutrients natural systems organic matter returned to the soil changes in organic matter
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agricultural practices often reduce OM ie: plowing, harvesting, weeding, erosion soils can become exhausted (happens a lot in tropics where warm and moist ) lose too much organic matter become unsuitable for plant growth attempts to maintain OM in soil add manure, compost, other organic materials change practices to reduce OM loss roots live in a very different environment damp low oxygen (other things using oxygen) complex communities of organisms root functions provide anchorage and support absorb water and minerals store extra food two types of root systems
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This note was uploaded on 11/15/2010 for the course PLPA 200 taught by Professor Darcy during the Spring '08 term at University of Illinois, Urbana Champaign.

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Oct 12 - OCT 12 LECTURE NOTES nematodes as plant pathogens what is soil root systems general nematode information soybean cyst nematodes soybeans

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