{"id":3001,"date":"2020-03-28T00:08:49","date_gmt":"2020-03-28T07:08:49","guid":{"rendered":"https:\/\/depts.washington.edu\/hortlib\/pal\/pal-question-630\/"},"modified":"2024-04-13T09:45:05","modified_gmt":"2024-04-13T16:45:05","slug":"cypress-tip-moth","status":"publish","type":"pal","link":"https:\/\/depts.washington.edu\/hortlib\/pal\/cypress-tip-moth\/","title":{"rendered":"Cypress tip moth"},"content":{"rendered":"

My Leyland Cypress is browning and has Cypress tip moth signs. I’m worried about the brown spots, and wonder if it can survive this attack? How can I control the pests, if it might survive?<\/strong><\/p>\n

 <\/p>\n

From what I can determine, your Leyland cypress (x Cupressocyparis leylandii<\/em>) trees are probably going to
\nsurvive this attack unless they are weakened in some other way.
\nx Cupressocyparis leylandii<\/em> in California survive the Cypress tip moth, though they can be unsightly. Since California is a bit too dry for this tree, the conditions are
\nnot identical, but Natural Resources Canada<\/a> does not
\nindicate that infestations are fatal. Because you said you found
\nevidence of tip moth (Cypress tip moth = Argyresthia cupressella<\/em>), I will
\nassume that is what the problem is, but a bit of browning, even in
\nconifers, is not unusual right after trees are planted. Be sure that you
\nare not overwatering, as one effect of that is the same as underwatering
\n(i.e., tip die-back or yellowing) because too much water prevents the
\nplant from taking water and oxygen into the roots.<\/p>\n

The Organic Gardener’s Handbook of Natural Insect and Disease Control<\/em><\/a>
\n(ed. by Ellis and Bradley, 1996, p.183) says about pine tip moth
\n(Rhyacionia frustrana<\/em>):<\/p>\n

“Handpicking works if only a few caterpillars are present. Pruning off
\nand destroying infested tips in winter is a very effective control.”<\/p>\n

I would recommend a prune-and-wait-and-see approach. April is a bit late to
\nprune (and puts root establishment in competition with shoot regrowth),
\nbut you may be able to slow the infestation down, so go ahead and do
\nit. Watch the trees this season and then prune again in the winter next
\nyear. Be sure to destroy (burn or bag and put in the garbage) the
\ndebris so you don’t reinfect your tree.<\/p>\n

A good gardening resource is the UBC Botanical Garden Forum<\/a>. Personal
\ntestimony\/experience is valuable, especially if it’s regional. (You
\nmight find it useful in the future.) Several people commenting about
\nx Cupressocyparis leylandii<\/em> note that it is not a very desirable tree; one of its
\nparents, the Cupressus nootkatensis<\/em>, also called Callitropsis
\nnootkatensis<\/em> or Chamaecyparis nootkatensis<\/em>, or, for that matter, plain Nootka cypress) is better. One person
\nrecommended planting small trees in the beginning, since they grow very
\nfast. This might save you some money, should you have to replace your
\ntrees. The site does not need a password; just click on “Search” in the upper right
\ncorner.<\/p>\n

Below is some additional information from Oregon State University<\/a> about cypress tip moth. This site recommends pesticides, but from everything I read, they are not
\neffective without multiple treatments. Since this pest is generally not
\nfatal to the trees, it is probably not worth it to use chemicals which would be dangerous and time-consuming to apply. If you know something about the
\nlife cycle of the pest, your observations will yield more information and any
\nmanual control attempts are more likely to be effective.<\/p>\n

Cupressocyparis<\/a>, <\/span>Insect pests–Control<\/a>, <\/span>Trees–Diseases and pests–Washington<\/a><\/div>\n","protected":false},"excerpt":{"rendered":"

My Leyland Cypress is browning and has Cypress tip moth signs. I’m worried about the brown spots, and wonder if it can survive this attack? How can I control the pests, if it might survive?   From what I can determine, your Leyland cypress (x Cupressocyparis leylandii) trees are probably going to survive this attack unless they are weakened in some other way. x Cupressocyparis leylandii in California survive the Cypress tip moth, though they can be unsightly. Since California…<\/p>\n

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