PERIODICALLY, late season outbreaks of pests such as thrips, jassids, cluster caterpillar, loopers and spur-throated locusts cause damage to the cotton canopy and/or flowers (eg. Figure 1). A key question for growers and consultants is will this damage affect yield? This question is important as spraying to control damage that won't reduce yield, incurs an unnecessary cost and selects for pest resistance. Whereas not spraying, if the damage is likely to reduce yield, risks lost income.We attempted to investigate this issue by opportunistically waiting for late season pest outbreaks to occur then either controlling them or leaving them uncontrolled. Severe outbreaks did not occur when we needed them to so we simulated the effects of pest damage manually. Although not exactly the same as 'real' pest damage, manual damage allows us to inflict known amounts of damage at set times so we can develop an understanding of the plants' likely response to real damage.
展开▼
