Current Conditions
The last couple of weeks in June were dry across the region, receiving only a fraction (0.05 inches) of the average expected rainfall for the month. Daytime high temperatures have been seasonal, night time lows are consistently below average. While the warm, dry weather is pleasant, lack of rainfall with increasing temperatures will cause environmental stress on landscape plants and lawns. Lawns are still growing and green, but carefully monitor moisture levels, with soil temperatures reaching an average of 72 degrees grass will quickly succumb without proper watering and maintenance. Plants in bloom currently include, but are not limited to; Kousa dogwood, butterfly bush, Catalpa, mountain laurel, Rosa rugosa, cinquefoil, inkberry, various species of hydrangea, Stewartia, American elderberry, some species of Spirea, Clematis, honeysuckle and many herbaceous plants. On average 126 growing degree days have been added during the last half of June, bringing the season total to 671. Of course as the growing season continues so do the potential pest problems, mosquito and tick populations are burgeoning and very active. Some previously discussed pests continue to plague the landscape while the life cycle of other early season pests is complete and still more threats are appearing across the region. Pest activity sighted and reported around the region includes; adult black vine weevils, Asiatic garden beetles, two-spotted spider mites, European chafer, imported pine sawfly and others.
Continuing Concerns
As the season progresses, weather changes and plants continue to grow so do pest populations. Discussed below are some current pests of concern, now being sighted and reported around the region. Mosquitoes and ticks continue to be of great concern, as vectors of disease you need to remember to always take measures to protect yourself from these pests. Contact your arborist regarding additional treatments to safeguard yourself, your property, your family and pests from ticks and mosquitoes.
Two-spotted spidermites is consider a warm season mite, and reproduces swiftly as temperatures increase. During warm weather their life cycle progresses from larva to adult within a couple of days while the heat discourages the production of predatory mites and decreases the ability of the plant to outgrow new feeding damage. Host plant damage can increase very quickly under these circumstances. Two-spotted spider mite is a generalist feeder and attacks many species of deciduous host plants.
The introduced pine sawfly larvae will be active during the first part of July and feeds on the same host plants as the European sawfly, including Mugho pine and other pine cultivars.
The European chafer is a scarab beetle which gathers in large numbers over night and can quickly cause serious feeding damage to host plants. Damage will be apparent during the day but the insects will not be visible. European chafer favors deciduous trees as host plants.
Asiatic garden beetles are also part of the night feeding scarab group of beetles. Habits are similar to those of the European chafer but for a preference for perennials, annuals and garden plants. Large, misshapen notches from feeding will be present at leaf margins.
Adult black vine weevils will be active soon if they are not already. These weevils seem mostly prefer Taxus species and rhododendrons. Adults spend the day beneath leaf litter, emerging at night to feed. Tiny, hemispherical notches along foliar margins will be visible when adult black vine weevils are active.
