Low Volume Applications

Citrus Greening

Low Volume Applications: An Emerging Technology in the Citrus Industry

Lukasz Stelinski, Michael Rogers, Jamie Yates, Megan Dewdney, Tim Spann

(Revised September 2009)

The spread of citrus greening and intense psyllid management programs has increased the cost of grove management yet the price for oranges has decreased. When putting those factors together, new ideas emerged as growers began to think of innovative ways to manage psyllids and the spread of greening more efficiently. Increasing use of low volume application technology to assist in the management of the Asian citrus psyllid has raised many questions and concerns within the citrus industry.

What are low volume applications?

Low volume applications are often compared to mosquito foggers, but they are not the same. Mosquito foggers distribute a cloud of drift that floats through the air, killing flying insects. When the droplets, if any, make contact with plants, buildings or humans, there is no longer any effectiveness because the active ingredient has been diluted in the air. Low volume applications have larger particle size than foggers and less drift. Low volume applications will slowly settle downward into the tree canopy for increased coverage and canopy penetration. Low volume applications should not be called fogging.

Low volume applicator

Why is there a need for low volume technology and what are the advantages?

A proper psyllid management program requires multiple seasonal sprays, therefore, increasing the management and material costs. Low volume sprays can be more cost effective, cover large areas quicker than conventional sprays and may potentially use less chemical per acre. The applicators are truck mounted, therefore, reducing the need to load and unload equipment and making transport between groves easier.

Mist-blower

Have low volume applications been proven to be effective?

Yes, low volume applicators have been found to be as effective as conventional sprayers for psyllid control. Research is being conducted to determine the effectiveness of spraying every row versus every other row and to optimize rates of currently available insecticides.

When are the applications made?

Low volume applicators create droplets with small particle size, therefore, calm conditions are required. Applications are made at night beginning around 10:00 pm and ending around dawn. The Florida Automated Weather Network (FAWN) is a resource used to determine if the weather conditions are suitable for application. Currently, it is believed that wind speeds above 10 mph are unsuitable and research is ongoing to verify this.

Applications should be made before a major flush to ensure that new growth is protected. Psyllid populations may build up to levels that are too high if large areas are not treated effectively before a major flush. If there is a psyllid population in the area, it will gravitate toward unprotected new flush and re-colonize it quickly.

Adult psyllid

During the spring and summer when psyllid populations are at a peak, foliar applications of insecticides against the psyllid are effective for only 2-3 weeks. Psyllids quickly re-colonize groves from surrounding habitats but low volume technology can help work against psyllid movement because large areas can be treated rapidly and spot treatments are easier.

What chemicals can be used for low volume applications?

Several chemicals are currently labeled for low volume use. Before applying any chemical with low volume applicators, read the label carefully. Remember, the label is the law.

Currently, the legal products are Agri-Mek 0.15EC, Danitol 2.4EC, Delegate WG, Dimethoate (at least 5 gallons per acre), Malathion 5 (at least 3 gallons per acre), Micromite 80WGS, Mustang, and Sevin XLR Plus. It is imperative to remember the potential of resistance with repeated chemical applications for all insects. Carefully plan your spray program to reduce the possibility of resistance. The Quick Reference Guide for Insecticides and Miticides can assist in the planning of a spray program (low volume, air blast, etc.) for various insects.

What are the disadvantages of low volume applications?

One potential disadvantage is that low volume applications need to be applied at night during calm wind conditions. This limited time window may make it slightly more difficult to plan applications and requires work during unconventional hours.

Night application

Research is still being conducted about the effectiveness of products, application methods and other uses for low volume applicators.

Resources

Atwood, Ryan and Lukasz Stelinski. November 2008. Is there a future for Low Volume application for psyllid control? Citrus Industry Magazine Volume 89 (Issue 11): 16

Atwood, Ryan and Lukasz Stelinski. 2008. Evaluation of Low Volume Application Technologies for Asian Citrus Psyllid (Diaphorina Citri Kuwayama) Control: Initial Results. Proceeding of the Florida Horticultral Society


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