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Showing posts from February, 2018

Curly Top Virus: Hints for Healthy Tomatoes

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Southwest Yard & Garden by Dr. Marisa Thompson Question: Last season all three of my tomatoes got curly top. Are there varieties that are more resistant? -Brittany E., Albuquerque, NM Answer: The short answer is no, but there are some interesting ways to increase your chances of tomato glory. Let’s start with general info about curly top virus. Dr. Stephanie Walker, our NMSU Extension Vegetable Specialist, talked me through the problem and the solutions. It is spread by one insect pest, the beet leafhopper (Circulifer tenellus; Fig. 1), which is known to maintain or increase populations while living on winter weeds like London rocket (Sisymbrium irio) and redstem filaree (Erodium cicutarium), among others. Timing is everything. When the winter weed hosts start dying at the end of their peak season, guess who has been recently planted and is ready to be the new habitat for the hungry beet leafhoppers and the viral disease they bring with them? Our precious tomato starts, that’s who (Fig…

Pruning Dos and Don’ts

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Southwest Yard & Garden  by Dr. Marisa Thompson Question: I get stressed this time of year because I know it is time to prune our landscape trees. Can you give some tips on how to prune with confidence? -Geri T., Albuquerque Answer: The task of pruning used to stress me out too. Every winter I’d watch a few YouTube videos, take some deep breaths, and then put pruning off for another time because I felt that my skills weren’t good enough to—cut it. It is actually good that you are reluctant to jump outside and whack away without an action plan. While some pruning may be necessary for safety and canopy manipulation, any time we cut into a tree we are creating a potential site for infection. One form of chronic tree torture is pruning annually just because. Tree wounds never heal. They can seal, but only if cut properly. At the base of each stem, where it meets the trunk, there is a special area called the branch collar (Fig. 1). Think of the trunk as wearing a short-sleeved shirt with the s…

White-Washed Tree Trunks Reduce Incidence of Southwest Injury on Trees with Thinner Bark

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Southwest Yard & Garden
by Dr. Marisa Thompson NMSU Extension Horticulture Specialist


Figure 1. Peach tree trunk painted white with a 50:50 solution of white latex paint in water at the NMSU Agricultural Science Center at Los Lunas. Photo credit: Marisa Thompson.

Question: Why have some people painted their tree trunks white?  -Shelly W., Las Cruces, NM Answer: Have you ever noticed bark buckling off the tree trunk? I first noticed it in a mature mulberry tree in my yard in Las Cruces a few years ago. The bark on the west side of the trunk had buckled so much that huge pieces looked like they were about to fall off. This phenomenon was likely caused by “southwest injury,” also known as “winter sun scald,” when the tree was young. Southwest injury is especially a problem in climates with intense sun exposure and extreme fluctuations between daytime and nighttime temperatures. In New Mexico, we are familiar with both. If my mulberry tree trunk had been painted in those early years when the…

New Mexicans are the First Line of Defense in Preparing for Emerald Ash Borer Attack

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Southwest Yard and Garden by Marisa Thompson Figure 1. Adult emerald ash borers are shorter than a penny (Howard Russell, Michigan State University, Bugwood.org).
Question: I’m concerned about the threat of the emerald ash borer in New Mexico. Should residents and cities be planting ash trees? -Concerned Citizen of Otero County via County Agriculture Agent, Sid Gordon
Answer: The first step in dealing with what looks to be an imminent invasion of emerald ash borer (EAB) in New Mexico is educating ourselves on how this pest works, what to look for, and how to report anything suspicious. Since 2002, when EAB was first identified in Michigan, it has killed or harmed hundreds of millions of ash trees in 31 states, including Colorado, Texas, Louisiana, and Oklahoma. Many experts believe New Mexico could be next on the list, especially considering the major interstates that connect New Mexico to Colorado and Texas. Scarier still, it could already be here and just not have been identified yet. The E…