Effects of Sustainable and Conventional Fertilizers on Plant Growth and Insect Life History Traits

1. Effects of Sustainable and Conventional Fertilizers on Plant Growth and Insect Life History Traits Katie England, Clifford Sadof Department of Entomology, Purdue University 13 December 2009

2. Introduction • Greenhouse growers are less likely to adopt sustainable production practices if they feel the difficulty or risk of switching practices is too great • (Hall et al. 2009)

3. Fertilizers • Conventional fertilizers • High energy inputs(Bhat et al. 1994) • Mining of phosphorus and potassium (Ludwick et al. 1995) • Potential for run-off and environmental degradation(Carpenter et al. 1998) http://www.noble.org/Ag/Economics/FertilizeOrNot/Fertilizer.gif

4. Commercial Alternative Fertilizer • Oilseed extract • Daniels Plant Food • P is from oilseed waste, not mineral deposits • Nitrogen composition • 73.5% NH3 • 19% NO3 • 7.5% other http://whyfiles.org/241GM_2/images/soybean_field.jpg http://www.gardeningthings.com/sm/cimpublic/retrieve.cgi?catalog_id=1.11.56

5. How Does Nitrogen Affect Plant Growth? NH3 • Plant Growth • Affected by nitrogen • Concentration (Stratton et al. 2001; Rose & White 1994) • Form (NH3 or NO3+) (Bar-Tal et al. 2001; Jeong & Lee 1992) • Potential for ammonium toxicity (Cox & Seeley 1984; Weigle et al. 1982) NO3+

6. How Does Nitrogen Affect Plant Pest Populations? • Insect Pests • Phloem feeders respond to nitrogen content of plants (White 1978; Jauset et al. 1998; Nevo & Coll 2001) • Whiteflies, aphids, mealybugs • Prefer higher N concentrations • Prefer certain N forms Purdue Extension

7. Hypothesis • Growth and development of plants and pests are determined by the concentration and the form of the fertilizer

8. Objectives • Evaluate the effects of various commercial fertilizers on poinsettia growth • Evaluate the effects of these fertilizers on insect pest life history traits Purdue Extension http://www.sxc.hu/photo/616668

9. Poinsettia Study • Fall 2008 • Poinsettia (cv. Prestige Early Red) • Long growing season • Easily manipulate pest infestation • Whiteflies are a key pest

10. Poinsettia Fertilizers

11. Poinsettia Growth 2 December Clear Excel Alt Daniels Osmocote 12 weeks after treatments began

12. Whitefly Life History Traits NS Not significantly different (n) Number of samples evaluated Linear Contrast: (F(1,24) = 9.64, P = 0.0048)

13. Poinsettia Amino Acids

14. Survivorship F(2,40)=10 P<0.001, R2= 0.334

15. Conclusions • Whiteflies • Whitefly survivorship showed no differences among plants fertilized with conventional and sustainable WSFs • Fecundity was lower on unfertilized plants and those fertilized with Daniels Plant Food than on plants in the other three treatments • Trends support a combination of both nutrient limitation/toxicity and plant defense mechanisms • Fertilizer does affect plant growth and pest development, however the effects of switching from conventional fertilizers to Daniels Plant Food are likely to be unnoticeable in a greenhouse setting

16. Acknowledgements Materials Donations: The Scotts Company Ball Horticulture Company Paul Ecke Ranch Premier Horticulture Myers Lawn & Garden Group Others: Nuris Acosta Claudia Kuniyoshi John Larson Julia Prado Marc Rhainds Christina Short Ariana Torres Damir Torrico Carlos Quesada Flor Quispe Guidance and Greenhouse Support: Dr. Cliff Sadof Dr. Roberto Lopez Dr. Luis Cañas Diane Camberato Rob Eddy Dan Hahn