- If you haven’t put out your alcohol based traps for Ambrosia beetles, it is best to go ahead and do so….but, it is getting late. Granulated Ambrosia beetles have already begun to emerge and control measures should be applied now. Other insect monitoring devices or methods should begin in earnest now.
- Watch for Azalea and Hawthorn Lacebug adults. Both of these pets are most active now (and again in August). Unlike most insects, the best time to control the Azalea and Hawthorn Lacebugs is during their adult stages. Montior plants such as azaleas and pieris for azalea lacebugs and hawthorns; monitor pyracantha and cotoneaster for Hawthorn Lacebug. Insecticides should be applied while these pests are most active.
Monitor evergreens for cool season mites and apply a miticide at this time. Plants that showed damage last summer are likely to already be infested.
- Boxwood and Holly Leafminor are likely be at most active peak during April so control measure should be introduced into the nursery or landscape site.
- Spray a fungicide to newly emerging foliage to reduce anthracnose, black spot, or powdery mildew on susceptible plants.
- Fungicide treatments for various diseases of conifers such as Juniper, Arborvitae and Leyland Cypress need to be made this month.
Weed scouting and control will continue through the month of May. Continue to scout for clearwing moth and various scale insects. Watch for the second flush of Hemlock Wooly Adelgid nymphs as these may pose a problem if left unchecked.
- Plan to place traps out for Japanese and Oriental Beetles as well as Mask Chafers. Likely adult flight patterns will start in early June, but there may be some micro-climate sites where you will see with earlier flight. Plan to apply insecticides to the foliage of susceptible species for adult control. (see archived blog post on Japanese Beetles in Feb. 2013 posts)
- Fireblight and Scab Control measures should be applied on crab apples, flowering pears, serviceberry, and hawthorn at this time.
- The second application of pre-emergent herbicides to landscape sites should likely take place mid to late May and into June.
- Apply insecticides for grub control in turf 10 days after finding adult Japanese and Oriental beetle adults in your traps. This will vary from year to year and typically is in late June to early July.
- The mountains are having a wet spring, therefore, a regular application of preventative fungicides may be necessary on many disease prone plants.
- Monitor for Brown Patch and other pathogens in cool season lawns.
- Monitor and apply control measures for needle cast fungi on Spruce, Pines, and Fir.
Article written by Glenn Palmer, Extension Master Gardener Volunteer.