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Providing evidence to improve practice

Action: Pest regulation: Use organic fertilizer instead of inorganic Mediterranean Farmland

Key messages

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Pest regulation (0 studies)

Crop damage (0 studies)

Ratio of natural enemies to pests (0 studies)

Pest numbers (2 studies): One replicated, randomized, controlled study from the USA found more aphids in plots with organic fertilizer, compared to inorganic fertilizer, in some comparisons, but another one found similar numbers of aphids in the same study system.

Natural enemy numbers (0 studies)

Supporting evidence from individual studies

1 

A replicated, randomized, controlled study in 1991 in a broccoli field in the Salinas Valley, California, USA (same study as (2)), found more pests in plots with organic fertilizer, compared to inorganic fertilizer. Pest numbers: More aphids were found in plots with organic fertilizer, compared to inorganic fertilizer, in one of eight comparisons (in plots with bare soil, on two of four sampling days: data reported as model results). Methods: Plots (10 x 10 m) had organic fertilizer (compost) or inorganic fertilizer (amounts not reported; four plots for each). Cabbage aphids Brevicoryne brassicae and green peach aphids Myzus persicae were sampled in each plot with two yellow pan traps (12 x 8 x 8 cm traps, 12, 22, 43, and 52 days after transplanting). Pests were also sampled by heat extraction from broccoli leaves (22, 32, 42, 52 and 62 days after transplanting).

 

2 

A replicated, randomized, controlled study in 1991 in a broccoli field in the Salinas Valley, California, USA (same study as (1)), found similar numbers of pests in plots with organic or inorganic fertilizer. Pest numbers: Similar numbers of aphids were found in plots with organic or inorganic fertilizer (data not reported).  Methods: Plots (10 x 10 m) had organic fertilizer (compost) or inorganic fertilizer (amounts not reported; four plots for each). Cabbage aphids Brevicoryne brassicae and green peach aphids Myzus persicae were sampled on 50 broccoli leaves from 50 plants in each plot (1990: every 2 weeks; 1991: every 10 days).

 

Referenced papers

Please cite as:

Shackelford, G. E., Kelsey, R., Robertson, R. J., Williams, D. R. & Dicks, L. V. (2017) Sustainable Agriculture in California and Mediterranean Climates: Evidence for the effects of selected interventions. Synopses of Conservation Evidence Series. University of Cambridge, Cambridge, UK.