July 3, 2010

1 - Slime mold is a strange landscape invader, but beneficial.

Yard and Garden - July 3, 2010


I found a strange substance in a dead area of my lawn. One day it was a bright yellow color, the next it was tan. It looked like a dog was sick on my lawn, but I do not have a dog and the yard is fenced. What is this strange stuff?

- K.K.

Los Lunas


This looks like a sighting of the strange organism know as slime mold. Your use of the word "strange" is very appropriate. This is an organism that feeds on decaying organic matter and microorganism causing the decay, hence its presence in the dead area of the lawn. It needs high moisture so irrigated lawns, areas of mulch that are kept moist, and most areas with dead organic matter during the monsoon become prime habitat for slime mold. Slime mold does little harm to living plant material. It can climb (and perhaps shade) grass leaves, but it does not cause diseases in them. As the slime mold feeds on dead plant matter and composting organisms, it releases nutrients that actually benefit surrounding, living plants. It can be washed away or brushed off any plants that it gets on. It is strange, but not harmful. Enjoy one of the very interesting residents of the microbial world when it comes to visit.

Blossom end rot can keep squash from developing.


My summer squash will not grow more than about three inches in length. They look normal but quit growing at about that length. I am also losing blossoms off of my tomato plants. I had this problem with the tomatoes once before and tried some high phosphorus fertilizer.

- T.G.



Blossom end rot may be the problem in the case of the squash (the end away from the stem turns black and the squash fails to develop). It is caused by hot, dry, windy conditions and dries the plant even if the soil is moist. Water carrying calcium necessary for the fruit development does not reach the developing fruit, so it stops developing.

Tomatoes are sensitive to high temperatures. If the temperature is too high, the pollen is killed and cannot fertilize the ovules, hence the fruit fails to develop and the blossoms fall. Smaller tomato varieties (cherry and pear tomatoes) have less problems, while the largest fruited varieties are most sensitive. Excess nitrogen fertilization can cause the production of beautiful tomato plants, but failure to develop fruit. Addition of phosphorus to balance the excess nitrogen may help if surplus nitrogen is the problem. If the problem is the high temperature, it will be overcome when (if) the monsoons arrive and temperatures drop.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.


For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms.

Send gardening questions to Southwest Yard and Garden - Attn: Dr. Marisa Thompson at desertblooms@nmsu.edu, or at the Desert Blooms Facebook page.

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