Location: Crops Pathology and Genetics Research
2012 Annual Report
This past year we again focused on research to better understand the ‘practical’ use of the microbial inoculant ‘Effective Microorganisms’ (EM•1® and activated EM•1®) produced by EMRO Inc. as both a foliar spray and as a soil amendment. The product has been acquired for US distribution by Teraganix (http://www.teraganix.com/) and is marketed in several different formulations. All of our work is now with product from this company. The focus of our research this year has been in five areas: compatibility with fungicides, insecticides, fertilizers, and beneficial nematodes; effect on seed germination and root and shoot growth; effect on water pH and plant nutrient use; effect on plant photosynthesis and shoot growth; and improved plant quality and reduce fungicide applications when used by cooperating growers in California.
In addition, during the past year we evaluated new reduced risk pest control strategies for their compatibility with natural enemies, examined the new mechanism underlying the ‘new’ petal mining behavior of Liriomyza leafminer on gerbera, compared/contrasted different sampling methods for the western flower thrips, and analyzed the impact of invasive species policy on the floriculture/nursery industry in the US.
Research with EM•1® and activated EM•1®
Solutions of the beneficial nematode Sterinernema feltiae in the infective juvenile (IJ) life stage are regularly applied to the growing media for control of several soil-dwelling pests (especially fungus gnats). We wanted to determine if applications of EM•1® and activated EM•1® would be compatible with these nematodes. We examined the effect on the IJ in solution (as would be applied by a grower) and on the IJ survival in the media after application. While this work is ongoing, there appears to be no negative compatibility issues.
The in vitro compatibility of EM•1® with common fungicides and METI (mitochrondrial electron transport inhibitors) miticides was evaluated in sterile MilliQ water. We evaluated compatibility based on survival of Lactobacillus spp. – a key ingredient in this microbial inoculant. Each pesticide solution was prepared using the highest label rate and included the most commonly used fungicides by the floriculture/greenhouse industry including Alliete® WDG, Bacillus subtillis, RootShield (Trichoderma harzianum), OHP Chipco® 26019, Pipron, Subdue MAXX, Systhane™ 40wp, and SuffOil-X. METI miticides and the insecticide/acaricides (Shuttle, Akari, Sanmite, Hachi-Hachi® [tolfenpyrad]). The latter four products were included because of the possibility of interference with electron transport in the microbial organisms making up the EM•1®. There was a great deal of variation across these different products, but most had little effect. However, OHP Chipco® 26019, Alliete® WDG, and Hachi-Hachi® were not compatible with these microbial inoculants.
The in vitro compatibility of EM•1® and activated EM•1® with fertilizer is being evaluated. We are interested in knowing whether the microbial inoculant can be used in conjunction with a fertilizer application without affecting performance. Undiluted fertilizer solution (17:5:17) at the recommended label rate is used and EM•1® or activated EM•1® were added to the fertilizer solutions or to a sterile MilliQ water control to make EM•1® and activated EM•1® dilutions of 1:100; 1:1000; and 1:10, 000. After predeterimined exposure periods each sample was plated onto selective media (selective for Lactobacilli or yeast) and survival determined by counting colony-forming units in each solution. Data are still be processed, but there appear to be no compatibility issues.
Influence on Seed Germination and Root and Shoot Growth
Reports from the literature suggest that seeds immersed in a solution of EM•1® or activated EM•1® have higher germination rates. To test this we immersed seeds from several bedding plants in a 1:1000 solution of EM•1® or activated EM•1® for 10 minutes; control seeds were immersed in water adjusted to the pH of the microbial inoculant solution. Results are not yet available from this study.
To evaluate root and shoot growth, seeds from various bedding plants have been sown into 288 cell flats using standard media. There are three treatments: water-only; EM•1® or activated EM•1® at 1:1000 at every irrigation; and EM•1® or activated EM•1® at 1:500 at every irrigation. There are five replications of each treatment with each replicate consisting of one 288 cell flat. After eight weeks, root and shoot growth will be determined. This study is not complete.
Effect on Nutrient Use and Water pH
We are interested in determining if fertilizer use can be reduced in plants being treated with EM•1® or activated EM•1®. The plan is to treat key bedding and container plant crops (e.g. gerbera and zinnia) with EM•1® or activated EM•1® at 1:500 dilution applied at every irrigation. Plants will be fertilized at 100 and 75 percent of the normal rate. The number of flowers and overall plant quality rating will be assessed at two, four, six, and eight weeks after start of treatments. There will be five replications of each treatment. This work has just been initiated.
Similarly, we have just begun the research on the influence of how EM•1® or activated EM•1® influence water pH. EM•1® or activated EM•1® will be added to 1L of sterile MilliQ water or Davis city water (average pH=8.4). Titration will be used to reduce the pH of each solution to 6.0. To determine the length of the effect of a single EM•1® or activated EM•1® treatment, the pH and EC of each pH 6.0 solution will be taken at one hour intervals for four hours using a HACH multi-parameter meter. This work is ongoing and depending on the outcome, this experiment may be repeated with different EM•1® or activated EM•1® rates and application protocols.
Effect on Plant Post-Harvest Quality Working with the postharvest group on the University of California, Davis campus, we examined whether applications of EM•1® or activated EM•1® made to cut roses could improve vase life. So far, we have not been able to show any difference. We are expanding this work to examine the post harvest life of bedding plants. This work has just been initiated. Key bedding and container plant crops (e.g. gerbera, zinnia and rose) are receiving EM•1® or activated EM•1® at 1:500 and 1:1000 dilutions applied at every irrigation. Plants are being treated over the entire production cycle and there is a water-only control. At the completion of the crop, finished plants will be brought to the post harvest group on campus for evaluation.
Reducing Fungicide Applications
Trials done with a cooperating grower in San Diego County revealed that regular applications of activated EM•1® made to Gardenia plants produced a quality crop without the need for fungicide applications. We evaluated the overall appearance/quality of the crop in addition to root and shoot dry weight. Other trials with cooperating growers did not provide such definitive results.
Thrips Sampling Methods for assessing thrips population density for pest management decision support are often inaccurate and/or imprecise due to thrips' positive thigmotaxis, small size, and naturally aggregated populations. Two established methods, flower tapping and an alcohol wash, were compared to a novel method, plant desiccation coupled with passive trapping, using precision and economic efficiency as comparative variables. Flower tapping was the least expensive method, in terms of man-hours, while the alcohol wash method was the most expensive. Precision, expressed by relative variation, depended on location within the greenhouse, location on greenhouse benches, and the sampling week, but was generally highest for the flower tapping and desiccation methods. Economic efficiency, expressed by relative net precision, was highest for the flower tapping method and lowest for the alcohol wash method.