Landscape Effects on Pest Management Clint Allen Ryan Jackson USDA-ARS-SIMRU

Transcription

1 Landscape Effects on Pest Management Clint Allen Ryan Jackson USDA-ARS-SIMRU Clint Allen Ryan Jackson USDA-ARS-SIMRU

2 MS crop acreage harvested 7 Corn Cotton Peanuts Rice Sorghum Soybean Sweetpotato

3 MS crop acreage harvested 4 Corn Cotton Peanuts Rice Sorghum Soybean Sweetpotato

4 Acres harvested in 1's No. insecticide applications per total cotton acres Insecticide applications targeting bollworms or TPB on cotton in MS Corn Cotton Soybean TPB sprays per acre BW sprays per acre

5 Host plants Bollworms and tobacco budworms > 23 host plants Tarnished plant bugs > 32 host plants

6 TPB nymphs per 5 row feet Crop hosts Corn favored host of bollworms Influx of TPB into cotton from corn during R2-R3 growth stage (Kumar and Musser 29) 6 TPB nymphs in soybean st 2nd 3rd 4th 5th AG465 6/8 6/1 6/12 6/14 6/16 6/18 6/2 6/22 6/24 6/26

7 Influence of local crop on insect populations in cotton fields R. A. Pickens and Son Farm (23-25) R. A. Pickens and Son Farm (Desha Co., Arkansas) Cotton, corn, soybean, rice Cotton sampled twice weekly 1 plants/field

8 Influence of local crop Crop types within a.25 mile buffer around each cotton field were estimated Relationships between monthly and yearly average of heliothine eggs and plant bugs and the percentage of various crops within buffer examined

9 Relationships between heliothine eggs and surrounding land All relationships with non-crop land were negative; yearly average significant in 2 of 3 years eggs and non-crop land Significant positive relationship with all corn June 24 and 25 Significant positive relationship with all cotton in August % non-crop land within.25 mi. of cotton R = P =.5 n = 65

10 Relationships between plant bugs and surrounding land Relationships with non-crop land mostly positive, only significant in July plant bugs and corn 4. All positive relationships with total corn, significant in 25 Significant negative relationship with cotton in 2 of 3 years % corn within.25 mi. of cotton R =.378 P =.6 n = 52

11 Mean rankings of heliothine eggs across 125 cotton fields Field rankings based on eggs per 1 plants - Lower rankings = greater no. of eggs

12 Mean rankings of TPB across cotton fields Field rankings based on TPB per 1 plants - Lower rankings = greater no. of TPB

13 Determination of nymphal hosts of TPB Plants having C 3 physiology Cotton Soybean Have less 13 C relative to 12 C C4 plants grasses Corn Sorghum Pigweed This ratio within the wings examined for tarnished plant bug host plants

14 Stable isotope analysis Wings cut and placed in tin capsules Elemental analyzer with isotope ratio mass spectrometer

15 Stable carbon isotopic ratios of host plants of the tarnished plant bug C 3 C 4 Shepard's purse Pigweed Henbit Daisy fleabane Curly dock Wheat Soybean Corn Cotton C Jackson et al.

16 Stable carbon isotopic ratios of tarnished plant bugs reared as nymphs on various plant hosts Shepard's purse Italian ryegrass Pigweed Johnsongrass Henbit Curly dock Daisy fleabane Wheat Corn tassels Corn ear C 3 C C Jackson et al.

17 % TPB from C4 Host % TPB from C4 Host % TPB from C4 Host % TPB from C4 Host TPB adults collected from cotton that developed as nymphs on C 4 hosts in MS Delta Cotton adjacent corn Cotton >1 mile from corn Jackson et al.

18 δ 15 N Stable carbon versus nitrogen isotope ratios for tarnished plant bugs reared as nymphs 1. Corn Pigweed δ 13 C

19 TPB adults collected from cotton that developed as nymphs on either corn or pigweed in MS Delta during 28 Cotton adjacent to corn Cotton >1 mile from corn 8 Corn Pigweed 8 Corn Pigweed /18 6/25 7/2 7/9 7/16 7/23 7/3 8/6 6/18 6/25 7/2 7/9 7/16 7/23 7/3 8/6

20 TPB adults collected from cotton that developed as nymphs on either corn or pigweed in MS Delta during 29 Cotton adjacent to corn Cotton >1 mile from corn 8 Corn Pigweed 8 Corn Pigweed /24 7/1 7/8 7/15 7/22 7/29 8/5 8/12 8/19 6/24 7/1 7/8 7/15 7/22 7/29 8/5 8/12 8/19

21 Summary The landscape may have major influence on populations of some insect pests in cotton Difficult to measure influence of the landscape Other variables involved Potential long-range movement of insects Unknown source of insects in cotton Tarnished plant bug is a better candidate for local landscape management Increased corn acreage has increased difficulty of management

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