Insect issues

The above-normal temperatures across much of the country this summer may have not been the best conditions for growing plants. And the warm temperatures certainly had an impact on insect populations.

Biological adjustments
Trisha Slater, sectional grower at C. Raker & Sons in Litchfield, Mich., said the warmer temperatures caused pest populations to go into overdrive.

“We started to incorporate a biological program last August,” Slater said. “In the past we were using a conventional spray program. This was really the first summer where we have had more bugs due to the fact that we aren’t spraying conventional chemicals anymore. We have to watch which chemicals we spray because of the biologicals. We’ve really had to change the way we do things.”

Raker hired another employee to handle IPM management including scouting and recording.

The two major pests this summer have been aphids and thrips.

“We have tried to incorporate biologicals that will go after these pests,” Slater said.

As a plug and liner producer, fungus gnats and shore flies are also a concern. Slater said the use of nematodes, which attack the larvae of these two pests, have been an effective control.

Initially, when Raker started using biologicals, they were used only in about an acre of the company’s 11 acres of greenhouses.

“We realized very quickly that we would have to treat the whole facility — that we just couldn’t treat one area with biologicals,” Slater said. “Because we are a plug and liner grower our crops stay here maybe on average five weeks. We move our product from range to range depending on the different stages of growth. And because of that, product that was only treated with biologicals moved into an area that was treated with conventional controls and that just didn’t work.

“We decided to treat the whole facility with biologicals. When we did that we really started to see the (pest) numbers start dropping,” Slater said.
 
For more: C. Raker & Sons Inc., (517) 542-2316; www.raker.com.

Increase in whiteflies
Timothy Johnson, grower at Orchard Mesa Greenhouse Inc. in Palisade, Colo., said he has seen an increase in whiteflies.

“We’ve started growing our poinsettias and we have seen a higher number of whiteflies than in the past,” Johnson said. “In the seven years that I have been here we have never really had to stay on top of whitefly infestations in our poinsettias. We always order our stock plants in April. This year all of our sticky cards have whiteflies and we are spraying Avid and other controls for them almost on a weekly basis and we still continue to see them. We are surrounded by orchards and vineyards. I’m sure they are coming from the orchards and possibly from infested stock material as well.”

The wholesale grower, which produces a mix of fresh cut flowers and flowering and foliage potted plants in 2 acres of greenhouses, did try to incorporate biologicals into a cut gerbera greenhouse.

“We wanted to change one of our cut flower greenhouses over to beneficials and start there and kind of build it up,” Johnson said. “We have a leafminer problem in that greenhouse. We didn’t end up sticking with the biologicals program because they couldn’t keep up with the leafminer.”

The company is trying some softer controls including horticultural oils. 

For more: Orchard Mesa Greenhouse Inc., (970) 434-4119.

Outdoor challenges
Regina Coronado, head grower at Stacy’s Greenhouses in York, S.C., said it was cooler in the beginning of the year, but by May things really started to heat up.

She oversees outdoor production on 285 acres at two locations.

“We had to monitor the plants much more closely,” Coronado said. “Also, when I was spraying before, it was every 10 days. This year I had to spray once a week. I have rotations because this is a huge farm.”

Coronado has a chart that has the hosts for each pest. “If we spray for Japanese beetles, we know that they will attack Rudbeckia ‘Goldsturm,’ salvias, echinaceas, heuchera and hibiscus. Every time we spray for Japanese beetles in those beds — regardless of whether or not they have the pest — we will spray them because eventually they will go to those plants. They migrate from one group of plants to the others.

“The Japanese beetle population was low and the season was short this year. But we had more flea beetles and more cucumber beetles. They are basically across the board and we saw more damage from them on sedums.” 
 
For more: Stacy’s Greenhouses, (800) 426-7980; www.stacysgreenhouses.com.