Bogash discusses biopesticide disease controls at conference
By DOROTHY NOBLE
(Editor’s note: This follows the related article of Steve Bogash’s presentation that appeared in the Feb. 14, 2017 issue of The Delmarva Farmer.)
STATE COLLEGE, Pa. (Feb. 21, 2017) — “Proper plant nutrition is the foundation of healthy plants,” Steve Bogash told his audience during the Farming for the Future Conference of the Pennsylvania Association for Sustainable Agriculture.
Bogash, an ISP Technologies advisor, then turned to strategies for pest control.
To get started, he advised being proactive, and “release predators and parasites early and often.”
He stressed scouting regularly, learning what to look for, and learning how to store and release beneficials, plus being aware of chemical interactions with beneficials.
Biocontrols work at different speeds than conventional controls, Bogash cautioned.
For instance, shelf life and temperature differ considerably.
He listed Regalia, Stimplex, Metabolik HV1 and Biostims, Bacillus subtillus, Bacillus amyloliquefaciens, Trichoderma, Streptomyces, bioblends such as Terra Grow, soaps and oils, potassium bicarbonate, coppers and sulfurs as examples of the range of products available.
To exemplify the learning curve, Bogash pointed out that not all coppers are the same.
Primary coppers include Kocide, Badge X2 and SC, and Cueva and copper soap.
Coppers are not systemic, and Mid-Atlantic soils are generally low in copper.
He suggested tank mixing coppers with Regalia to enhance efficacy.
Competition, antagonism, antibiosis, and enhanced nutrient uptake explain how various biocontrols work.
Occupying the rhizosphere and/or phylloplane (root zone and leaf and flower respectively) can suppress or prevent pathogens from invading the plant.
Hence, the control competes against the pathogen.
However, there must be high densities of the biological control agent before pathogen attempts at entry.
In antagonism, the parasitic biological control agent attacks and feeds on the pathogen.
Here also, the bioagent must be present before or at the same time as the pathogen.
Production of secondary metabolites known as toxins (antibiotics for example) prevent germination or inhibit the growth of pathogens.
In this case, high densities of the bioagents may not be required, but the antibiotic action needs to be expressed before the infection occurs. This is antibiosis.
Enhanced nutrient uptake results from treatment of a bioagent. Treated plants are often larger.
This can take place by altering the pH or through the enzymatic breakdown of insoluble elements.
The uptake of fertilizers can be increased. Also, the fungal hyphae from the beneficials often reach beyond the root hairs.
Bogash contrasted system acquired and induced host resistance.
He said that when exposed to certain biological products, many plants will produce salicytic and jasmonic acids.
In traveling to other parts of the plant, it signals tissues to activate natural defense mechanisms.
The pathway starts with exposure to a pathogen, which then causes the plant to fire one or more protective mechanisms.
An example is the potential for protection from gray mold on aerial parts of the plant when a beneficial is inoculated through the roots.
In systemic acquired resistance, a plant is exposed to a pathogen; that stimulates salicylic acid which then stimulates one or more specific proteins. Some protection from disease results. Bogash pointed out that Actigard works that way.
For induced systemic resistance, the plant is exposed to a non-pathogenic microbe.
This stimulates jasmonic acid and ethylene, which in turn stimulate phytoalexins and enhanced cell walls.
Since the cell walls actually thicken, the plant has additional disease protection.
Turning to insect and arthopod management, Bogash listed soaps and oils, pyrethrum, spinosad, Neem/Azadirachtum, Beauvaria bassianas, Met 52 (Metarhizium anisopliae), Grandevo, Venerate, Preferal (Isaria spp.), Bacillus thuringiensis, and beneficials and predators.
Pyrethrum is often the first line of defense for Colorado potato and cucumber beetles.
It includes Pyganic, and some products have Neem oil.
It has a fast knockdown, but it acts poorly on brown marmorated stink bug. Broad spectrum and toxic to bees, it is also not compatible with bio-based systems.
The spinosads include SpinTor, Conserve and Entrust.
Their action is intended for Colorado potato beetle, thrips and leafminers.
The label includes asparagus, cole crops, bulbs, berries, cucurbits, tomatoes, grapes, herbs and leafy vegetables.
This group is broad spectrum.
Beneficials and predators include ladybird bettles, lacewing, Orius, plus aphid and spider mite predators.
Bogash noted that predators have preferences.
Ladybird beetles work well for peppers and other smooth leaves and fruit. They can control most aphids.
Orius/minute pirate bugs also control aphids, plus tackle Western flower thrips and spider mites.
Also good for smooth vegetables, these work better in hot weather — they are not as effective early in the season.
Bogash said lacewings are good general purpose predators, and will work on tomatoes.
(Editor’s note: The last portion of Bogash’s presentation will appear in a subsequent issue. It will include data on applications of several new biocontrol materials, information on spider mite and whitefly controls, and Bogash’s biocontrol strategy of seasonal controls, plus scheduling adaptation for high tunnels.)