Protecting Melons From Silver Leaf Whitefly

Avoid Planting Near Earlier Planted Crops

By Patrick Cavanaugh, Editor

Silver leaf whitefly can be a severe yield-robbing pest in melons, but there are ways to prevent the damage, according to Tom Turini, a UCANR Vegetable Crops Adviser in Fresno County.

“A tactic is going to depend upon planting. If you’re able to put the crop into an area where you’re not next to earlier planted melons or cotton or known sources of whitefly, your likelihood of experiencing damaging whitefly levels is going to be lower,” Turini said. “Growers can’t always do that, but that’s part of the approach when you can. You’ll limit your risk.”

Tom Turini, UCANR Farm Advisor, Fresno County

Turini said the pest could mainly be a problem when you’re putting in those late melon fields when whitefly populations are higher.

“Whiteflies are not good fliers, so when you put those fields in areas where you don’t have sources of whitefly nearby then you will have less pressure for sure,” Turini said.

“Then there are some insecticide programs that you can look at, particularly when you know you’re going to have pressure,” Turini explained. “If you’re coming into high temperatures, and you’ve got late-planted melons, you may want to start with soil-applied insecticides, through the drip. It could be Admire; also Sivanto is a newer material that that has registration and has shown efficacy in desert production areas, which have much higher pressures and more consistent pressures than we do in the San Joaquin Valley.”

2018 Cotton Crop Proceeding Well

Late Season Pests Can Be a Challenge

By Patrick Cavanaugh, Editor

The 2018 cotton harvest will be starting in the southern part of the Central Valley later this month, and some growers will be facing pressure from pests.

California Ag Today recently spoke about the topic with Dan Munk, a UC Cooperative Extension Farm Advisor in Fresno County specializing in irrigation crop nutrient management and cotton production systems.

“The crop looks very good and loaded with cotton bolls. We don’t have a lot of boll losses, and that’s a real positive thing, so very excited about the potential for fairly high yields in the 2018 season. The biggest concern right now is pest management, press pressures as we approach the latter part of the season,” Munk explained.

The main issue this time of year is the honeydew that pest leave on the cotton. Honeydew is the exudate extracted by the insect as it feeds on the leaves.

“Because we have the bolls on the plant that have opened, we now have exposed lint and need to protect that lint from stickiness that’s created from whitefly and the aphid honeydew, which is basically the added sugars that those insects that feed on the leaves of the plant, and they excrete them and deposit them on the lint,” Munk said.

Munk explained that the big concern right now is dealing with pest pressures in terms of whitefly and aphid—both sucking insects. “The problem right now [is] where we’re seeing pest pressures—particularly from whitefly as we get later in the season—will build in many fields.

There are several approaches to controlling whitefly and aphids. One is to deal with the eggs that they produced. And then there’s a certain class of materials to deal with the eggs.

“There’s another class of materials that deal with the juveniles—that early form of the insect—and then there are ways to control the adults,” Munk said.

“A number of insecticides have been applied to deal with those various levels of insect populations based on the individual field situation,” he explained.

Aza-Direct Stops Insect Feeding

Aza-Direct Targets Critical Pests

By Patrick Cavanaugh, Editor

Aza-Direct, with the active ingredient Azadirachtin, is one of the most potent, reduced risk insect pest controls among all the natural pesticides.

With four modes of action, Aza-Direct targets critical pests such as spider mites, thrips, whitefly, aphids, and lygus. It’s very safe with beneficial insects, especially bees, to help maintain the natural balance within the crop.

The product has a lot of excellent benefits regarding those four modes of action, explained Patrick Holverson, Director of Ag Business with Parry America Inc., which manufactures the active ingredients for Aza-Direct.

“Because of the four modes of action, you will not get a resistance buildup like you can with standard chemicals,” Holverson said. “What I like about it, many growers in California will apply Aza-Direct in anticipation before the target pest hits because it is not a contact killer; it takes two or three days to get into the pest’s system to reduce the population.”

Furthermore, the material is an excellent repellent and as well as an anti-feeding agent.

“Those pests who stay in the treated field will experience severe feeding cessation due to a locked jaw and digestive system,” Holverson said. “So, the pests that do feed on the plant, the material acts as an insect growth regulator that affects both the eggs and the larva, preventing them from reaching maturity.”

Holverson said that in strawberries, Aza-Direct controls two significant pests—including two-spotted spider mite and lygus—that come in after losing their host crop.

“The product prevents puckered strawberries and increases the value of the crop,” he said. “It can be used on both organic and conventional crops.”

It has a zero-day pre-harvest interval, and four-hour re-entry, which is essential in a crop such as strawberries.