Achim Dobermann, deputy director general for research at the International Rice Research Institute (IRRI; http://irri.org), and Leigh Vial, head of IRRI's experiment station, begin IRRI Agronomy Challenge II. It is the continuation of a special project in which they demonstrate how to grow a productive rice crop in a 25 x 100-meter field on IRRI's research farm.
In this installment, IRRI entomologist Finbarr Horgan joins Leigh in the field to discuss what is going on regarding pests, pathogens, and predators at this stage of the crop.
Commentary from Leigh:
At 58 days after transplanting, the crop is around panicle initiation and looks a picture now. 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 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 (each to their own, Finbarr!), are clever creatures. After many seasons of molluscicide application, they can sense it coming and shelter by climbing up into the foliage and leaving the water. Clever? Maybe. But by definition, a pest population will evolve to adapt to any control regime we dream up...we have selected the clever ones! Note: Achim also talked about the Golden Apple Snail during last year's Challenge.
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 its can capture enough fuel from the sun.
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