By Shari Thomas
CSU Extension Master Gardener
Q: A branch on my crabapple tree is black and wilted, but the rest of the tree looks fine. It bloomed nicely, but the petals seemed to wilt rapidly. Is there a problem with my tree?
A: Your tree may have a bacterium called fireblight. It is especially destructive to apple, pear, quince and crabapple trees, and appears about the time of petal fall. The bacteria overwinter in blighted branches and at the edge of cankers or sores on the bark. Sometimes you will see oozing at the site of the sore. It is very easy to spread the bacteria, so consult PlantTalk at www.PlantTalk.org [1] and read script #1411 on “Fireblight” for more information. There is not excellent control for this disease; selecting resistant crabapple varieties is the best prevention. If you prune the diseased branches, make sure you sanitize your tools between each and every cut.
Q: My sprinkler system came on even though it rained a lot this week. My lawn doesn’t need the extra water, but it’s hard to remember to shut the system off. What can I do about it?
A: There are inexpensive rain shut-off sensors (around $25) for your sprinkler system that measure rain fall and automatically shut off the sprinkler system if sufficient rain occurs. No need to waste water, and excessive lawn watering can encourage potential problems.