Fall Ornamental Pest Update--From Syngenta

This information is provided from Lee Bloomcamp with Syngenta which I am relaying to you. If you would like to find more information about a specific pesticide label you can visit this site <http://www.cdms.net/Label-Database>.

Disclosure -The use of trade names or registered products in this publication is solely for the purpose of providing specific information.  UF/IFAS does not guarantee or warranty the products named, and references to them in this publication do not signify our approval to the exclusion of other products of suitable composition.  All chemicals should be used in accordance with directions on the manufacturer's label.  Use pesticides safely.  Read and follow direction on the manufacturer's label. 

Weather extremes have had significant impact in Florida in recent months.  Heat, drought, monsoons and hurricanes have affected nurseries all over the state, and pest and disease management problems continue as well.   Current issues are addressed below.

Insects

This time of year it is not unusual to find  large white grubs in both in-ground and container tree and shrub roots.  The grubs are immature scarab beetles, mostly Masked chafers, Green June Beetles, and May Beetles, some have multiple-year life cycles.  Adult beetles deposit eggs in moist rich soils, and  irrigated areas full of peat, bark and juicy roots attract egg-laying females.  Grubs feed all summer, then move to the soil surface to pupate in the fall, making them more visible to growers. The mature grubs are hard to kill since they are not eating- DuraGuard drenches may work, but most treatments are not cost effective.  Best strategy for control starts in early summer.  Adult beetles emerge in spring, then mate, and lay eggs.  May-early July drenches of Mainspring GNL or Flagship or other labeled products readily control smaller grubs, preventing root damage and plant stress.   Entomopathic nematodes and milky-spore bacteria are also used in grub IPM programs.  Scarab beetles often return to the same areas to breed, so watch for grubs and root damage and prepare for drenches next year.

Red Imported Fire ants increase activity in the fall.  Less rain, cooler temperatures and plenty of food stimulate colony growth.  Broadcast baits are the best way to control RIFA in areas larger than ½ A.  Award II is labeled for nurseries, and Advion RIFA bait can be used around structures, lawns and non-production areas.  Advion is extremely fast and effective, and will be available for use in nurseries soon.  Treating for RIFA  now will reduce winter survival, and lead to fewer ant problems in the spring.

Diseases

‘Tis the season for mildew, both Powdery and Downy.  Cooler evenings, mature foliage and drier weather all promote these diseases.  Both can be hard to identify, and easily mistaken for other problems.  Many species get powdery mildew, and downy is expanding its host range as well.  Attached are recommendations for both.  Downy mildew is a big problem on basil- Micora, Subdue Maxx and Heritage are all labeled for control of DM on this crop.  Most DM products also control phytophthora.