Agriculture Reference
In-Depth Information
important in young trees. Avoid overhead irrigation, and use the practices on
Control aphids, leafhoppers, and other insect pests.
Chemical and biological control.
Applying Bordeaux mix, fixed copper, or
fixed copper plus horticultural oil sprays at or slightly before bud break can
reduce or delay inoculum development in cankers that you missed during
spring pruning.
Tetracycline and streptomycin applications (be sure to use organically
acceptable products) during mid- and late-bloom can protect blossoms and
developing fruits. These products do not appear to protect against infections
to shoot tips and leaves.
Several biological products can help reduce fire blight infections. They do
not give complete control, but they can be part of an integrated program.
Do not use biological and copper products together, nor apply biological
products within 7 days of applying an antibiotic. Two types of biological,
blight-control products are presently listed with OMRI. Blight Ban A506
(
Pseudomonas fluorescens
strain A506) is best applied during early bloom.
Serenade (
Bacillus subtilis
strain QST 713) products act rather like antibi-
otics and should be applied with other biological products in mid- to late-
bloom, rather than during early bloom.
Rust Diseases
Many related rust pathogens attack pome fruits, including cedar-apple rust
(
Gymnosporangium juniperi-virginianae
), Pacific Coast pear rust (
Gymno-
sporangium libocedri
), quince rust (
Gymnosporangium clavipes
), and Amer-
ican hawthorn rust (G
ymnosporangium globosum
), among others. Together,
these rusts have a wide range of hosts, including hawthorn, saskatoon, apple,
crab apple, mayhaw, medlar, and quince. Unlike most fungal pathogens that
can survive on a single host, these rust fungi require at least two different
hosts in order to complete their life cycles. Plants in the Cypress family serve
