Utilisation of plant functional diversity in wildflower strips for the delivery of multiple agroecosystem services

Published source details Balzan M.V., Bocci G. & Moonen A. (2016) Utilisation of plant functional diversity in wildflower strips for the delivery of multiple agroecosystem services. Entomologia Experimentalis et Applicata, 158, 304-319.
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This study is summarised as evidence for the following.

	Action	Category
	Crop production: Plant flowers Action Link
	Pollination: Plant flowers Action Link
	Pest regulation: Plant flowers Action Link

Crop production: Plant flowers

A replicated, randomized, controlled study in 2011–2012 in an organic tomato field near Pisa, Italy, found more and bigger tomatoes on plants grown next to some combinations of planted flower species, compared to other combinations, or compared to bare ground. Crop yield and Implementation options: The most and biggest fruits were found in 2011 on Roma tomato plants grown next to flower strips with three species (140 fruits/plant; 195 g dry biomass/fruit), which had more and bigger fruits than those grown next to bare ground (55 fruits/plant; 50 g dry biomass/fruit) or next to flower strips with either six or nine species (40–65 fruits/plant; 35–40 g dry biomass/fruit). The number of fruits/plant varied with the number of flower species/strip (three/strip: 35–140 fruits/plant; six/strip: 40–95; nine/strip: 35–50; bare ground: 30–55), as did fruit biomass (three/strip: 35–195 g dry biomass/fruit; six/strip: 35–70; nine/strip: 40–65; bare ground: 35–50), but not all differences were significant in both years (2011–2012), or both tomato varieties (Roma and Perfect Peel). Methods: Four treatments were compared: three flower species/strip (Apiaceae species), six species/strip (three Apiaceae and three Fabaceae), nine species/strip (three Apiaceae, three Fabaceae, and three others), and a control strip with no flowers. Three strips/treatment were sown with flower seeds (2011: 6 and 21 June; 2012: 13 and 17 June). Each flower strip (2 x 4 m) was positioned between two tomato plots (4 x 10 m/plot; one Roma plot and one Perfect Peel plot). Number of fruits/plant was assessed for five plants/plot and dry biomass was assessed for four fruits/plant.
Pollination: Plant flowers

A replicated, randomized study in 2011–2012 in an organic tomato field near Pisa, Italy, found similar numbers of wild bees in planted flower strips with different numbers of flower species, in most comparisons. Implementation options: More wild bees were found in flower strips planted with nine plant species, compared to three or six species, in 2012, but similar numbers were found in other comparisons (numbers of individuals not reported). Methods: Three treatments were compared: three flower species/strip (Apiaceae species), six species/strip (three Apiaceae and three Fabaceae), and nine species/strip (three Apiaceae, three Fabaceae, and three others). Three strips/treatment were sown with flower seeds (2011: 6 and 21 June; 2012: 13 and 17 June). Each flower strip (2 x 4 m) was positioned between two tomato plots (4 x 10 m/plot). Bees on flowers were sampled with aspirators every 14 days, after flowering began.
Pest regulation: Plant flowers

A replicated, randomized, controlled study in 2011–2012 in an organic tomato field near Pisa, Italy (same study as (7)), found more damage by caterpillars, but not aphids, in tomatoes grown next to flower strips, compared to bare ground. It also found more individuals and species of natural enemies in flower strips, compared to bare ground. Crop damage: More damage by caterpillars, but not aphids, was found in tomatoes grown next to flower strips, compared to bare ground (amounts of damage not reported). Natural enemy numbers: More individuals and species of ground-dwelling predators were found in flower strips than on bare ground (16–19 vs 4 individuals; numbers of species not reported). Implementation options: Less damage by caterpillars was found in tomatoes grown next to flower strips with more compared to fewer flower species (six or nine species vs three, in 2012, in plots with high numbers of fruit/plant; amounts of damage not reported). Fruit damage varied with the number of flower species/strip, but not all differences were significant in both years or in both varieties (Roma and Perfect Peel; amounts of damage not reported). Fewer tomato pests (sap-sucking bugs), but more generalist pests (Lygus sp. and Nezara viridula), were found in strips with nine flower species, compared to three (numbers of individuals not reported; same results as (7)). Flower strips with more, compared to fewer, flower species (six or nine vs three species) did not have significantly more natural enemies (ground-dwelling: 16–19 individuals/strip; flower-visiting parasitoids: 12–19; flower-visiting predators: 4–7; same results as (7)). Strips with six flower species had more species of flower-visiting natural enemies than strips with three or nine flower species, but did not have significantly more species of ground-dwelling natural enemies (numbers of species not reported). The diversity of flower-visiting natural enemies increased over time, but the number of individuals did not (numbers of individuals and species not reported). Methods: Four treatments were compared: three flower species/strip (Apiaceae species), six species/strip (three Apiaceae and three Fabaceae), nine species/strip (three Apiaceae, three Fabaceae, and three others), and a control strip with no flowers. Three strips/treatment were sown with flower seeds (2011: 6 and 21 June; 2012: 13 and 17 June). Each flower strip (2 x 4 m) was positioned between two tomato plots (4 x 10 m/plot). Ground-dwelling predators were sampled with pitfall traps every 7 days, and natural enemies on flowers were sampled with aspirators every 14 days, after flowering began. Damage by pests was assessed for 30 fruits/plot and 12 leaves/plot.