IRRI Agronomy Challenge 2: Healthy predators, happy rice, and clever snails

Author // Dr. Achim Dobermann Categories // Achim Dobermann's blog

15 February

At 58 days after transplanting, the crop is around panicle initiation and now resembles a picture. Yes, a picture of vigorous rice, but also a picture of pests, pathogens, and predators in something of a balance. The hybrid still looks bigger, but the inbred has had a good week and caught up some. Despite Nancy Castilla and her team surveying for about an hour, there is not much in the way of damage from critters or pathogens to observe. Whorl maggot is around—or at least it was last week when Nancy looked—but it seems to be declining fast. Nancy found no major difference between the hybrid and the inbred. I was expecting the hybrid to be more susceptible to things that bite, chew, and infest. Finbarr Horgan explained it well in the field today: modern hybrids have a much broader genetic base than the early hybrids, so there is probably more range in susceptibility within hybrids or inbred varieties than between hybrids and inbreds. Generalizing is dangerous.

With such serenity in the field and apparently no need to spray any insecticide or fungicide at all, we currently have the luxury of just thinking about the last fertilizer application, which will be done next week according to the Nutrient Manager.

The learning for the week came from Finbarr in the field. Our friends the golden apple snails, in addition to allegedly having beautiful faces (to each their own, Finbarr!), are clever creatures. After many seasons of molluscicide application, they can sense it coming and they take shelter by either burrowing down or climbing up into the foliage. Clever? Maybe. But, by definition, a pest population will evolve to adapt to any control regime we dream up … and we have selected clever ones!

golden apple snails in rice plants

Golden apple snails and an egg mass

I think our yield targets look quite achievable at this juncture. The days are sunny and getting sunnier, and this is exactly the time when that converts to yield potential. The leaves are fully extended and the photosynthetic machine can run its fastest if it can capture enough fuel from the sun.

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About the Author

Dr. Achim Dobermann

Dr. Achim Dobermann

Achim is a soil scientist and agronomist with 25 years experience working in Asia, North America and Europe. He is recognized internationally as an authority on science and technology for food security and sustainable management of the world's major cereal cropping systems. He has authored or co-authored over 250 scientific papers and two books on nutrients in rice and has received numerous awards from various academic, government and industry organizations. He is a Fellow of the American Society of Agronomy and a Fellow of the Soil Science Society of America.

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