Stout presentation on Insect Infestations in Relation to Rice Crop Phenology. Advanced rice entomology training at rice research station in Crowley, La on March 2, 2011

1. Insect Infestations in Relation to Rice Crop Phenology Michael Stout Department of Entomology LSU AgCenter/LSU A&M

2. When do Rice Pests Attack? AND To What Extent can We Predict Attack? Insect Infestations in Relation to Rice Crop Phenology OR

7. If we had reliable answers to each of these questions, we could predict attack with reasonable certainty Unfortunately, we don’t have reliable answers for many pests Whether or not the pest is causing economic losses is a related, but separate issue

8. Let’s apply these principles to the best-studied rice pest in Louisiana, the rice water weevil… Adult overwintering Larval feeding Mating and oviposition Adult feeding

10. Population dynamics of the rice water weevil over the growing season Emergence of the rice water weevil from overwintering does not begin until early April in most years, and may not be complete until late May… April May June % emergence from overwintering

11. Population dynamics of the rice water weevil over the growing season April May % emergence from overwintering … but less is known about population fluctuations during the season and return to overwintering June June July August Weevil population densities

13. Oviposition (egg-laying) by rice water weevil is triggered by flooding… Treatment/Flood depth Eggs per plant 0 10 20 30 40 50 dry soil wet soil 1.3 cm 5.1 cm 10.2 cm c bc bc b a

15. Suitability of rice for oviposition changes as rice grows and develops

19. We lack basic information (on population dynamics, environmental effects, plant susceptibilty) for most other rice pests… So, we are less capable of predicting attack by these pests