The groundwork for MISA started back in early 2009 when citrus canker disease in Florida began causing significant loss in citrus production, negatively impacting the Florida fresh fruit market.
Aggressive use of Copper (Cu) pesticide was not sufficient to fully control disease spread. An improved version of Cu or a Cu alternative was highly desired. Dr. Swadeshmukul Santra of the UCF NanoScience Technology Center (NSTC) in collaboration with Dr. James H. Graham of University of Florida Citrus Research and Education Center initiated an exploratory project on copper bactericides/fungicides with an initial goal to improve Cu bioavailability and develop more effective Cu formulations.
Dr. Graham initiated a field trial (“Monahan – Grapefruit trial” in Vero Beach) in April-May, 2009 to evaluate field efficacy of Cu loaded silica nanogel materials (UCF “CankicideTM” technology), and the journey began.
After a successful trial year, the team realized the potential of CankicideTM technology, thanks to CRDF for providing research support to continue canker trial. Improved field efficacy at lower rate compared to industry standards was demonstrated.
With active industry collaboration, CankicideTM technology has been developed to a stage that is commercially viable, with the potential of moving forward in seeking EPA registration.
However, non-copper agro-chemical alternatives are urgently needed for minimizing Cu resistance development and toxic heavy metal exposure to the environment.
While Santra focused primarily on Citrus Canker, Huanglongbing (HLB), also known as Citrus Greening, became a bigger threat in Florida groves.
HLB is a century old bacterial disease, which has devastated citrus groves globally, including major citrus producing countries (USA, Brazil and Mexico), causing billions of dollar crop losses every year.
In Florida, over 90% of citrus trees are believed to be infected with HLB and orange production has dropped to 81.5 million boxes (2015-2016 season), a record low yield in the past 50 years. Texas and California citrus industry are just a few years behind Florida to becoming endemic.
HLB causing bacteria, Candidatus Liberabacter asiaticus (CLas) is restricted to phloem tissue, thus requiring a therapy that must be delivered systemically to become effective.
Therapeutic agent must be small enough to be mobilized systemically. The particulate sizes should be comparable to phloem proteins or even smaller so that they can easily travel between plant cells or through cellular pores. After the job is done, the therapeutic agent must be decomposed and cleared through metabolic pathways so that it is safe to the plant, the environment and ultimately human health.
Santra conceived the idea of protein sized small (<5.0 nm) particle laden therapeutic technology while attending the International Research Conference on Huanglongbing (IRCHLB) in 2013, leading to the invention of ZinkicideTM.
Graham and Johnson evaluated field efficacy of ZinkicideTM. ZinkicideTM demonstrated unprecedented efficacy in grapefruit canker trial and HLB. Efforts are currently underway to register ZinkicideTM with US EPA.