>>Date: Wed, 26 Jun 2002 05:32:35 -0700 (PDT) >>From: Michael Smith <[EMAIL PROTECTED]> >>Subject: Re: Root Aphids >>To: Allan <[EMAIL PROTECTED]> >> >>Allan, >> >>Please Fwd: >> >>I remember reading an article years ago, which I >>followed up with naked-eye observations in the field. >>The article stated that aphids were feeding on >>something called "honey dew"; a black sweet dew that >>forms on plants. This is easily observable developing >>on field peas during humid periods; a good reason to >>use 508 on the plants.
Yes! This is a must time to use l508 >> >>Anyway, if mycorrhyzae is the technical term for honey >>dew, I would say Hugh is right on the money. Ah, but mycorrhyzae is not a technical term for honey dew. Mycor (fungus) rhyzae (root) is a technical term for a class of fungi that colonize the fine feeder roots of plants, taking over the job of root hairs on the hairy roots. Where root hairs extent out into the soil an almost imperceptible fraction of an inch (really only visible under a microscope) mycorrhyzae are easily seen as a fuzz on the hairy roots. These symbiotic fungi do live off the sugary sap (honey dew if you please) in the plant but they are NOT the honey dew itself. They can increase the nutrient uptake of the plant, as I previously stated, by a factor of ten or more since their hyphae (another technical term for the vessicles or strings of cells) can extend out into the soil as much as a quarter inch or more from the roots they colonize. I've heard of a half an inch. Cultivation disturbs these. Water logging from heavy rains also ruins these hyphae. They have to have plenty of oxygen. Fungus in general needs air. You never get any fungus on cheese, for example, unless air gets to it. So these symbiotic fungi need air. They seem to also need such trace elements as copper and boron, as they do not seem to get going well in soils deficient in these two elements, and perhaps others. Their further symbiotes, azotobacters, need manganese, cobalt and molybdenum to say nothing of plenty of calcium if they are to fix nitrogen in symbiosis with the mycorrhyzae. That's another story. Enough for now. Mycorrhyzae are not honey dew, they eat honey dew. Best, Hugh What I >>would watch out for is its' appearance above the soil >>line; it limits the health of the plant. >> >>Michael >>>Ant and aphids on roots is just about always a good >>>sign. Ants cultivate the mycorrhyzae so there is a >>>surplus for the aphids. >>> >>>Best, >>>Hugh >> >><Hugh - I thought ants on the roots, among other >>things, indicated poor soil structure. It seems so >>degenerate, aphids on the roots (I don't recall seeing >>ants, myself). >> >>(Moving right along) Are you saying that the aphids >>are only feeding on exudates and not on the plant >>itself? >> >>-Allan> >> >> >> >>__________________________________________________ >>Do You Yahoo!? >>Yahoo! - Official partner of 2002 FIFA World Cup >>http://fifaworldcup.yahoo.com Visit our website at: www.unionag.org
