What is in this article?:
- Pomegranate growers face threat of black heart disease
- Weed control
- Root wreckers and mites
- Heart rot diseases may go undetected initially and are a major challenge to pomegranate growers.
Root wreckers and mites
• Mike Konda, with the Fresno County Department of Agriculture, discussed management of gophers, terming them “root wreckers.”
Aside from damage the critters do to trees and plants, he said, they also can cause water loss as it pours into old gopher tunnels.
Owls are natural predators, Konda said, advising that it’s best to choose “old barn wood” over new plywood when building an owl box.
Macabee traps can be used to kill gophers, he said, along with strychnine. The poison can be dispensed with a machine pulled behind a tractor intersecting the burrow runs. Or it can be placed by hand using probes.
• David Haviland, UC farm advisor in Kern County, talked of insects and mites that pose problems for growers of pomegranates.
Among them is the cotton aphid, which was also discussed by Larry Godfrey, UC Cooperative Extension specialist with UC Davis.
Godfrey and Haviland talked of how the cotton aphid over-winters in pomegranates, and then migrates to other crops where it can cause significant damage. For example, it may carry the tristeza virus into citrus.
The damage it causes in pomegranates includes reduced shoot growth, damage to leaves, honeydew on fruit, rotten spots where fruit touch and sooty mold on the outside of fruit.
There are biological controls, Haviland said, along with chemical controls that include Lannate.
For pheromone management, Godfrey said, it’s best to combine two compounds, nepetalactone and nepetalactol. Use of neonicotinoid pesticides is being challenged because of the effects on bees.
Another pest is the tiny citrus flat mite, which causes scabbing of the fruit starting at the stem end. Sulfur dust or wettable sulfur can be used to control the pest, and Haviland said the wettable sulfur is less harmful to beneficial insects.
Katydids can cause damage by biting fruit, resulting in a “corky patch.” Delegate and Lannate are among pesticides that can be applied, Haviland said, cautioning growers to be sure to check the labels.
The leaf footed plant bug can open the way to secondary infection and it also can be controlled with Lannate.
The grape mealybug can leave honeydew deposits that lead to sooty mold, Haviland said. Material for control includes Applaud.
Other pests include the omnivorous leaf roller, which Haviland said can be controlled by using degree days to time treatments.
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