Ecological Archives A016-055-A3

Alejandro C. Costamagna and Douglas A. Landis. 2006. Predators exert top-down control of soybean aphid across a gradient of agricultural management systems. Ecological Applications 16:1619–1628.

Appendix C. Mean (± SE) of large- and small-size predators (individuals / m2) and parasitoids (L. testaceipes mummies / m2) for different combinations of agricultural management system and predator manipulation treatments, within the large field cages in the aphid population increase experiment the Kellogg Biological Station Long Term Ecological Research (KBS-LTER) site during 2003.


Date

Predator treatment

Agricultural treatment

Big predators

Small predators

Parasitoids


21 July 2003

Exclusion

Conventional

0.00 ± 0.00

1.34 ± 0.95

2.12 ± 1.62

   

No-till

0.00 ± 0.00

0.00 ± 0.00

0.00 ± 0.00

   

Zero-chemical input

0.00 ± 0.00

1.32 ± 1.32

1.95 ± 0.72

 

Sham

Conventional

0.67 ± 0.49

0.71 ± 0.71

0.42 ± 0.42

   

No-till

0.17 ± 0.17

0.00 ± 0.00

0.43 ± 0.43

   

Zero-chemical input

0.33 ± 0.33

1.07 ± 0.50

0.91 ± 0.41

 

Open

Conventional

0.33 ± 0.21

2.75 ± 1.23

0.00 ± 0.00

   

No-till

0.17 ± 0.17

0.46 ± 0.46

0.46 ± 0.46

   

Zero-chemical input

0.50 ± 0.34

0.28 ± 0.28

0.37 ± 0.37

28 July 2003

Exclusion

Conventional

0.00 ± 0.00

0.79 ± 0.79

13.22 ± 8.66

   

No-till

0.50 ± 0.50

2.02 ± 1.17

7.66 ± 7.66

   

Zero-chemical input

0.00 ± 0.00

0.00 ± 0.00

21.73 ± 20.27

 

Sham

Conventional

1.17 ± 0.48

14.28 ± 5.20

1.29 ± 1.29

   

No-till

0.50 ± 0.34

0.00 ± 0.00

0.00 ± 0.00

   

Zero-chemical input

0.50 ± 0.34

1.85 ± 0.85

0.00 ± 0.00

 

Open

Conventional

0.17 ± 0.17

4.64 ± 2.45

3.07 ± 1.57

   

No-till

0.00 ± 0.00

4.48 ± 4.48

3.21 ± 1.56

   

Zero-chemical input

0.17 ± 0.17

1.68 ± 0.79

2.47 ± 1.35


† Large-size predators were counted through 3-minute non-intrusive visual sampling within the whole cage and included H. axyiridis, C. septempunctata, nabids (Heteroptera: Nabidae), and spiders (Aracnidae).  Small-size predators and mummies were counted by a detailed, intrusive search on 10 (7-21) and 6 (7-28) plants per cage and were adjusted to m2 by multiplying the average per plant by the total number of plants within the cage.  Small-size predators included: O. insidiosus, first and second instar coccinellid larvae, syrphid larvae, predaceous fly larvae (Diptera: Cecidomyiidae and Chamaemyiidae), and lacewing larvae (Neuroptera: Chrysopidae).



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