Professional Agriculture

The following is a poster that was presented at the 2010 annual meeting of the American Phytopathological Society of America, Charlotte, NC

MeloCon WG® and SoilGard 12G® used in a program as a methyl bromide alternative to control nematodes and soil borne diseases in fruiting vegetables

H. Brett Highland, PhD. Certis USA, Nokomis, FL 34275

Introduction

With the advent of the Montreal Accord of 2007 on restricting ozone depleting gases, and as a result of further state initiated restrictions, the use of methyl bromide and other fumigants in agriculture has been on a steady decline. Effective and safe alternative treatments are being investigated, labeled and used in commercial production. The loss of fumigants is especially deleterious to the production of fruiting vegetables, primarily tomatoes and peppers, in the southeastern US, where soil borne diseases and nematodes can be of particular concern. A program of MeloCon® WG and SoilGard® 12 G, marketed by Certis USA, have been shown to be very effective when used alone or in combination to control nematodes and soil pathogens in field trials in the US.

Melocon WG® is a granular formulation containing spores of the fungus Paecilomyces lilacinus strain 251 a naturally-occurring beneficial fungus from soil. It is used as an inundative release bionematicide for control of plant parasitic nematodes that prevent establishment of healthy plants and decrease yield . Melocon controls a wide range of plant parasitic nematode species (see Table 1). It attacks all life stages of the nematode (eggs, immatures, and adults). It has a 0 day PHI, 4 hr. REI, and a signal word “Caution”. The common commercial rate is 4 lbs/acre, and the common use pattern in fruiting vegetables is outlined below. Melocon is a wettable granule formulation, and can be applied through the irrigation system (drip tape) applied on bed tops and incorporated then watered in, or drenched into transplant holes before or after transplanting.

Treatment / Time of treatment 2 weeks ± 3-4 days before transplant 2 days before transplant 2 weeks after transplant ± 3-4 days 4 weeks after transplant ± 3-4 days Note 6-8 weeks after transplant ± 3-4 days
MeloCon
4 lb/a through drip
Yes - drip No Yes-drip No There must be 3-4
days between the applications of MeloCon & SoilGard
Yes if needed- drip
SoilGard
5 lb/a through drip
Yes–greenhouse, 1 lb/100 gal drench to transplants Yes - drip No Yes - drip   Yes if needed- drip

SoilGard® is a granular formulation containing spores of the fungus Gliocladium virens strain GL-21 (also known as Trichoderma virens), a naturally-occurring beneficial fungus from soil. It is a preventative fungicide for control of “damping off” diseases that prevent establishment of healthy plants and decrease yield. The fungus in SoilGard directly attacks and kills pathogenic fungi, parasitizes any that survive, and prevents re-infestation by competitive exclusion. It is effective against a wide range of plant pathogens in fruiting vegetables (see Table 2). SoilGard can be applied in a flexible application regime for tomatoes, including a transplant drench while seedlings are in the greenhouse, chemigation, drench at plant, or soil incorporation pre plant. It has a 0 day PHI & REI, and a signal word “Caution”. The typical commercial rate is 5 lbs/acre, and the use pattern in fruiting vegetables is outlined above.

Replicated field trials using Melocon and SoilGard compared to standard chemical alternatives were conducted in Florida and California from 2007 to 2010 with fruiting vegetables and looking at the control of common nematode and soil disease pathogens.

UTC (left), treated with MeBr (middle), and SoilGard/MeloCon right), 4 weeks after planting.
(From B. Booker, FLAG, Dover FL).

Tomato plant showing symptoms of southern blight disease. (From B. Booker, FLAG, Dover FL).

Tomato roots showing symptoms of southern root knot nematode galling damage

Table 1. MeloCon – Plant Parasitic Nematode Control Spectrum

Root knot Meloidogyne spp.
Burrowing Radopholus similis
Cyst Heterodera and Globodera spp.
Reniform Rotylenchulus reniformis
Spiral Helicotylenchus spp.
Sting Belonolaimus spp.
Root lesion Pratylenchus spp

Table 2. SoilGard- Disease Control Spectrum

Pepper blight Phytophthora capcici
Damping off Pythium spp., Rhizoctonia solani
Fusarium crown rot Fusarium oxysporum
Southern blight Sclerotium rolfsii
White mold Sclerotini spp.

Materials and Methods

The trials (results below) were conducted in small block replicated and randomized manner under normal growing conditions for the areas under consideration. Normal commercially acceptable pest control techniques were employed. Tomato or pepper transplants were normally set into 50:50 methyl bromide:chloropicrin fumigated soil in plastic-mulched, raised beds unless specified otherwise (below). Transplants were irrigated and fertilized through drip tape. Treatments were arranged in a randomized complete block design with (usually) four blocks, each in a separate bed. The plot size varied according to trial, but was large enough to conduct plant sampling and yields when required (usually 10 plant samples). The products SoilGard and Melocon were applied by injecting through drip tape irrigation systems. Applications were begun when pest pressure was indicated or seasonally when normal applications would have begun in commercial situations. The number of applications of products and intervals are indicated in the figures. Normal commercial fungicide programs for foliar disease or insecticide programs for foliar pests were applied and were commercially acceptable. All experimental plots received normal commercially acceptable herbicide applications. If harvests were made tomato fruit were harvested two to three times and marketable fruit counted and weighed to determine total yield. Plant root knot ratings or root damage ratings, or disease incidence and severity ratings were made periodically in each plot as needed.

Drip Tape Injection

Sample of drip tape injection tanks used in commercial production.

Sample of drip tape injection tanks used in commercial production.

Experimental rig for treating small plots (from M. Azores-Hampton, UFL, Immokalee, FL)

Results and Discussion

MeloCon Against Southern Root Knot Nematode in Tomatoes, D. Seal, University of Florida, Homestead, FL, 2009. Fig. 1 and 2. – MeloCon when used at 4 lbs/acre through the drip significantly reduced root galling in tomato caused by southern root knot nematodes. Control was slightly better than shown with Vydate. The control of root knot nematodes and their corresponding damage increased fruit yields compared to the untreated control.

Figure 1- MeloCon Against Southern Root Knot Nematode in Tomatoes, Root Gall Rating
(D. Seal, University of Florida, Homestead – 2009)

Four applications MeloCon at two weeks pre plant, at plant, and 2 and 4 weeks post plant,
Vydate six applications at 2-8 pts/a according to plant size.

Figure 2- MeloCon Against Southern Root Knot Nematode in Tomatoes, Yield (Lbs/plot)
(D. Seal, University of Florida, Homestead – 2009)

Four applications MeloCon at two weeks pre plant, at plant, and 2 and 4 weeks post plant,
Vydate six applications at 2-8 pts/a according to plant size.

SoilGard Against Pepper Blight Phytophthora capsici in Pepper , D. Holden, Holden Agricultural Research and Consulting, Camarillo, California , 2009. Fig 3. – SoilGard when used at 5 lbs/acre through the drip significantly reduced incidence of pepper blight in pepper, and control was slightly better than shown with Ridomil plus phos acid. The control of pepper blight and the corresponding damage increased fruit yields compared to the untreated control (data not shown).

Figure 3. SoilGard Against Pepper Blight Phytophthora capsici in Pepper , Incidence / plot,
(D. Holden, Camarillo, CA - 2009)

Three applications SoilGard , one pre plant as a transplant drench at 1 lb/100 gal, and two applications at 5 lb/a at 3 days and 4 weeks post plant. Three applications of Ridomil Gold SL at 1 pt/a plus Phos acid at 3 day, 4 and 6 week post plant.

SoilGard Against Fusarium Crown Rot in Tomato, Glades Crop Care, Hobe Sound – Florida , 2007. Fig. 4 – SoilGard when used at 5 lbs/acre through the drip significantly reduced incidence of Fusarium crown rot in tomato, when applications took place close to artificial inoculations with the pathogen.

Figure 4. SoilGard Against Fusarium Crown Rot in Tomato, Severity / plot (0-10),
(Glades Crop Care, Hobe Sound- Florida – 2007)

Two applications SoilGard at 4 lbs/a, 4 day pre plant and 28 day post plant applications.
Inoculated with Fusarium oxysporum 27 days post plant.

MeloCon Against Stubby Root Nematode in Tomato, Florida Agricultural Research, Dover, Florida , 2010. Fig. 5,7 – MeloCon when used at 4 lbs/acre through the drip significantly reduced root damage in tomato caused by stubby root nematodes. Control was slightly better with methyl bromide compared to MeloCon in this trial. The control of stubby root nematodes and their corresponding damage increased fruit yields compared to the untreated control, and yields were slightly higher than methyl bromide in this trial.

Figure 5. MeloCon Against Stubby Root Nematode in Tomato, Root Rot Rating (0-10),
(Florida Ag Research, Dover – 2010)

MeloCon applied twice post plant at 4 lb/a , once 20 days after plant, and once 60 days after plant., then watered in with in 0.5 in./a water. Methyl bromide 50:50 was applied at 150 lbs/a 12 days prior to plant.

Figure 6. SoilGard Against Southern Blight in Tomato, Incidence / plot,
(Florida Agricultural Research, Dover – 2010)

SoilGard applied pre plant as drench 1 lb/100 gal, and twice post plant at 5 lb/a at 2 days post plant and again 30 days later. Methyl bromide 50:50 was applied at 150 lbs/a 12 days prior to plant.

SoilGard Against Southern Blight in Tomato, Florida Agricultural Research, Dover, Florida , 2010. Fig. 6,7 – SoilGard, when used at 5 lbs/acre through the drip significantly reduced plant damage in tomato caused by southern blight. Control was slightly better with methyl bromide compared to SoilGard in this trial. The control of southern blight and the corresponding damage increased fruit yields compared to the untreated control, and yields were slightly higher than methyl bromide in this trial.

Figure 7. MeloCon Against Stubby Root Nematode and SoilGard Against Southern Blight in Tomato,
Yield lbs/ 4 plots combined,
(Florida Agricultural Research, Dover – 2010)

The use of MeloCon and SoilGard along with herbicide applications in replicated field trials compared to standard chemical fumigants or nematicides resulted in comparable control of soil borne pathogens and nematode pests, resulting in improved plant growth and increased yield. The use of these products in conjunctions with other effective fumigants now being developed and marketed give growers viable options to methyl bromide for fruiting vegetable production in the challenging SE US vegetable growing areas.