Molly Cadle-Davidson
Molly Cadle-Davidson Chief Science Officer, ABM

Molly Cadle-Davidson first started with ABM as a consultant in 2013, but it wasn’t long before she was working full time as assistant chief scientific officer in January 2014. Now as chief science officer, she works to enhance ABM genomics strategies and to foster next-generation product development. Cadle-Davidson is an expert in the field of genetics and is well versed in the application of genomics and next-generation sequencing techniques for trait-based research and development. Prior to joining ABM, she was involved in government work with SRC, Inc. and aided other government-funded programs with the Departments of Homeland Security, State, Defense and Justice. While at SRC, Inc., her work resulted in one trade secret, two patents pending and one patent application currently being prepared for the company. Cadle-Davidson holds a Bachelor of Science in genetics from the University of California, as well as a Master of Science in plant pathology from Washington State University and a doctorate in plant breeding and genetics from Cornell University.

The effectiveness of biologicals is simply amazing. For example, miniscule amounts of the legume inoculant rhizobia can influence nodulation, plant growth and development, nitrogen fixation, soil nitrate levels, and plant yield.

If we put rhizobia on a legume seed and plant the seed in the ground, the seed and the rhizobia begin surveilling their surroundings, including each other, ultimately developing the synergistic relationship resulting in all these benefits.

In theory, we could put one rhizobia cell on that seed as a starter inoculum. That cell will divide to create more cells. Bacteria and fungi both do this; in fact, some grow into the plant root and live with that plant all season long. Theoretically, one cell is all it takes; however, due to the harsh seed treatment conditions, environmental stresses, and sampling error, we need to target delivery of many more than that. This is definitely not an argument for second-guessing application rates.

To deliver the optimal number of cells, or microbes, to a seed, we must think about what those cells are experiencing during the seed treatment process: there will be loss on the way. We need to ensure there are enough cells making it through being mixed with other chemicals or salts, being atomized or forced through a spray nozzle, and being stored for a variable length of time.

Product formulations and CFU (colony forming unit) specs are designed to accommodate these factors and still get the number of cells on the seed by the time of planting that will ensure effective starter inoculum amplification, colonization, and performance.

In the end, there is plenty of science to support the efficacy of small amounts of cfus per seed as being effective, owing to the fact that living biologicals reproduce themselves. That said, living biologicals react differently to conventional ag input handling processes than chemistries and inerts do, being much more susceptible to these harsh conditions.

Thus, successful products have been adapted through innovative formulations and delivering far higher CFUs than are actually necessary in order to ensure grower success in the field.