Effects of Sustainable and Conventional Fertilizers on Plant

Growth and Insect Life History Traits

Katie England, Clifford SadofDepartment of Entomology, Purdue University

13 December 2009

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)

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

• 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

Commercial Alternative Fertilizer

http://www.gardeningthings.com/sm/cimpublic/retrieve.cgi?catalog_id=1.11.56

How Does Nitrogen Affect Plant Growth?

• 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)

NHNH33NHNH33

NONO33++NONO33++

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

Hypothesis

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

• Evaluate the effects of various commercial fertilizers on poinsettia growth

• Evaluate the effects of these fertilizers on insect pest life history traits

Objectives

Purdue Extension

http://www.sxc.hu/photo/616668

• Fall 2008• Poinsettia (cv. Prestige Early Red)

– Long growing season – Easily manipulate pest infestation– Whiteflies are a key pest

Poinsettia Study

Poinsettia Fertilizers

Treatment   Fertilizer   N P K  

Conventional WSF

Peters Excel (15-5-15 The Scotts Co.)

200 29 167 (ppm)

Sustainable WSF

Daniels Plant Food (10-4-3 DP Foods, LLC)

200 40 58 (ppm)

Controlled Release

Fertilizer

Osmocote PLUS (15-9-12 The Scotts Co.)

1.4 0.35 0.91 (g/pot)

Alternation WSFs - - -

No Fertilizer   Clear Water   - - -  

Poinsettia Growth

Clear Excel Alt Daniels Osmocote

12 weeks after treatments began

2 December

Whitefly Life History Traits

Linear Contrast: (F(1,24) = 9.64, P = 0.0048)

Fertilizer Survivorship

(SEM) W-D (n)

Fecundity (SEM)

W-D (n)

Clear Water 0.414 (0.070) C 9 24.07 (8.49) NS 6

Excel 0.754 (0.057) AB 9 42.85 (4.98) NS 8

Alternation 0.829 (0.049) AB 10 45.37 (5.16) NS 5

Daniels 0.863 (0.049) A 10 25.67 (5.89) NS 9

Osmocote 0.735 (0.030) B 10 39.11 (3.09) NS 9

F=13.37, df=4,34 P<0.0001 F=2.45, df=4,23 P=0.075 NS Not significantly different(n) Number of samples evaluated

Amino Acids (nmol/ mg)

Fertilizer n Total (SEM) W-D Essential

(SEM) W-D

Shikimic (SEM)

W-D Shik/ Ess

(SEM) W-D

Clear Water 8 7.56 (2.10) C 0.894

(0.426) B

0.392 (0.190)

B 0.603

(0.099) A

Excel 8 12.98 (3.29) BC

1.19 (0.334) B 0.442

(0.090) B

0.488 (0.10)

AB

Alternation 9 19.29 (3.20) B

2.53 (0.521) B 0.710

(0.119) AB

0.308 (0.028)

BC

Daniels 9 38.99 (5.96) A

5.02 (1.08) A 1.20

(0.146) A

0.413 (0.032)

BC

Osmocote 9 15.44 (3.71) B

2.01 (0.576) B 0.792

(0.215) AB

0.274 (0.035)

C

F=8.37 df=4,30

P=0.0001

F=6.03 df=4,30

P=0.0011

F=3.77 df=4,30 P=0.0135

F=5.31 df=4,29

P=0.0025

Poinsettia Amino Acids

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

Su

rviv

ors

hip

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0.0 20.0 40.0 60.0 80.0

Total Free Amino Acids (nmol/mg)

Su

rviv

ors

hip

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

Acknowledgements

Guidance and Greenhouse Support:

Dr. Cliff SadofDr. Roberto Lopez

Dr. Luis Cañas Diane Camberato

Rob EddyDan Hahn

Materials Donations:The Scotts Company

Ball Horticulture CompanyPaul Ecke Ranch

Premier HorticultureMyers Lawn & Garden Group

Others:Nuris Acosta

Claudia Kuniyoshi John Larson Julia Prado

Marc Rhainds Christina ShortAriana TorresDamir Torrico

Carlos QuesadaFlor Quispe