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Peak Fire Blight Season

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Southwest Yard & Garden by Dr. Marisa Thompson
I’ve got good news and bad news. I’ll give you the good news first. Fire blight, one of the oldest known bacterial plant diseases, only affects plants in the rose family. Celebrate that factoid for a nice long moment. 
The bad news is that the rose plant family includes lots of common ornamental and fruiting trees and shrubs that we love in New Mexico. According to Phil Lujan,Diagnostician for NMSU’s Plant Diagnostic Clinic, “We are smack in the middle of peak fire blight season and so far we have diagnosed at least 7 positive samples from all around the state with another 5 more pending that just arrived from Bernalillo County.” Lujan added that ornamental pears, followed by edible pears, apples, and photinia are the “usual suspects.”
This week I’ve selected a column on fire blight from July 2018 to reprint with a few updates. The NMSU Plant Diagnostic Clinicanalyzes plant material for plant pathogens and environmental stresses and sugg…

Fasciation Fascination

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Southwest Yard & Garden by Dr. Marisa Thompson
Question: What is ailing this sotol plant, and can you suggest a remedy? -J. Linnell, submitted via Bernalillo County Extension Agent Sara Moran Answer: I see why you’re concerned about your sotol. In the center, where the 5- to 20-foot-tall flower stalk should be, there’s a squished-up clump of spiny stems that look like a pile of curly green lizard tails. I’ve never seen anything quite like this before, but it looks to me like it could be a type of fasciation.Fasciation is an abnormal growth condition that is usually associated with hormonal imbalances within specific plant tissues—often, and in this case, in the floral stem. Like animals, plants produce hormones that act as mobile chemical signals and control all kinds of physiological processes throughout the entire life of the plant.Plant hormones (aka phytohormones or plant growth regulators) are involved in everything from the exact timing of seed germination and flowering to frui…

Act Now to Control Squash Bug Populations

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Southwest Yard & Garden




Question: Squash bugs decimated my plants and my crop last summer. What should I be doing now to prevent this from happening again?  -Sarah H., Las Cruces
Answer: You are not alone, and I’m glad you’re already gearing up. Last year I addressed multiple questions about controlling squash bugs in September and October columns. However, by then, most squash bug problems were beyond help, and I promised to address this issue earlier this year.This week, I’ve collected recommendation snippets from archived columns going all the way back to 2008.  Click these links to go to the full columns, or scroll down to get the gist: "Short Answers to Pressing Questions: Rotting Fruit, Summer Pruning, and Squash Bugs"- August 26, 2018 "Pheromone Signals and Dusty Deterrents"- October 09, 2019 (includes details on using kaolin clay and diatomaceous earth!)

Supporting Pollinators & Beneficial Insects in Backyards and on Farms - FREE WEBINAR SERIES

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Southwest Yard & Garden Weekly Gardening Column for New Mexico

Bad Combo: Chlorosis and Water Stress

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Southwest Yard & Garden by Dr. Marisa Thompson See additional recommendations from Doña Ana County Extension Horticulture Agent Jeff Anderson AND retired Urban Forester George Duda in the ADDENDUM at the end of this column! Raywood ash tree (above) and single leaf (below) showing classic symptoms of iron deficiency (yellowing of the tissue between the leaf veins) in a Rio Rancho landscape. Photo credits M. Hobson. Question: We have a Raywood ash that’s probably eight years old and huge. The tree has done so well; however, this year I noticed it is more of a light lime green instead of a true green. I am wondering if we need to amend the soil with anything. I did put 10-10-10 in its drip line two months ago, and it gets watered approximately every 10 days.-M. Hobson, Rio Rancho (submitted via NMSU Extension Agriculture Agent for Sandoval County, Lynda Garvin)Answer: This looks like classic chlorosis that’s common in our region due to lim…

Juvenile Reddening: Red Tips & Purple Leaves on New Growth Help Plants Manage Stress

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Southwest Yard & Garden by Dr. Marisa Thompson
Question: Why is new growth at the tips of some plants distinctively redder than older leaves?-Yours Truly, Los Lunas, NMAnswer: I’ve been noticing young reddish-purplish leaves on otherwise green plants, and it makes me wonder what benefits these colors might have for the plants themselves. Past columns on other pigment-related questions have been the most liked, clicked, and shared compared to any other topic. In the most popular weekly column I’ve published so far, “What Does Red or Green Really Mean?- Phytochemical Coloration in Chiles,” assistant professor of horticulture at NMSU Dr. Ivette Guzman helped me understand why pigments are so cool in chile peppers: “The diverse colors on peppers are indicators that they are rich in phytochemicals, whether they be sweet, hot, or sweet and hot. Three main classes of phytochemicals are responsible for these pretty pigments. Chlorophyll is commonly associated with greenness. Carotenoids ar…