Response of alate aphids to green targets on coloured backgrounds

Abstract

To study the effect of background colour on aphid landing on green targets (water pan traps), two field experiments were set up in Hessen, Germany, in 2003. Traps were put onto coloured plastic sheets (13 colours, straw mulch, transparent foil, and uncovered soil, Experiment 1). In Experiment 2, green water pans were again put on coloured plastic sheets (red, white, green, and yellow), and the sheets were either sprayed with insect glue or not. Backgrounds and traps were spectrally characterised with a field radiometer (320 -950 nm). Aphid catches were highest in the traps on the uncovered background, and lowest in the traps on white or silver backgrounds. For Brevicoryne brassicae , Myzus persicae (Homoptera: Aphididae, Macrosiphini) and five further aphid species, there was a significant negative correlation between UV-reflectance (320 -400 nm) and log(N + 1)-transformed number of individuals. However, the effect of straw mulch (reduced aphid catches with straw compared to the uncovered background), could not be attributed to differences in UV-reflectance, as UV was almost identical in soil and straw. High numbers of alate aphids were caught in traps with dark backgrounds (e.g. black, dark green), a result which was attributed to the high contrast between the background and target. The substantially higher aphid numbers from targets with bare soil than from targets with spectrally similar black backgrounds were thought to be caused by the structure of the background surface: for alate aphids, landing close to the target on smooth surfaces may induce probing, and the lack of appropriate substrate will result in take-off, whereas soil will not induce probing, and aphids will continue to move towards the green targets.

Aphid populations (Hemiptera: Aphidoidea) depend of mulching in watermelon production in the Mediterranean region of Croatia

“…The attractiveness of black and straw mulches for Aphis spp. was also reported by Döring et al (2004). Furthermore, the attractiveness of straw mulch for M. persicae was observed at Pula in 2008 at a time close to the aphid population maximum, whereas the attractiveness of bare soil was noted during the period of aphid population decrease.…”

“…During the season of 2011, two assessments at Pula demonstrated the attractiveness of black PE mulch to aphid populations. According to Döring et al (2004), high numbers of winged aphids were captured in traps on dark backgrounds (black and dark green). While studying the effect of coloured mulches on pest populations, Farias-Larios & Orozco-Santos (1997) found that aphids were most numerous on bare soil and black mulch.…”

“…According to Adlerz & Everett (1968) and Wolfenbarger & Moore (1968), yellow and, to a lesser degree, orange mulches attracted M. persicae, whereas aluminium and silver mulches repelled this pest. Döring et al (2004) noted that catches of M. persicae in green water traps were highest on bare soil, followed by dark green mulch, and lowest in traps on a white or silver background. The cowpea aphid A. craccivora was less attracted to black mulch, whereas the abundance of A. gossipii was low in traps over clear mulch .…”

“…Clear mulch could be a practical management tool for reducing aphid populations, increasing yield, and enhancing fruit quality in watermelons under tropical conditions (Farias-Larios & Orozco-Santos, 1997). Döring et al (2004) reported that 15 types of mulch attracted fewer aphids than unmulched soil. Additionally, Walters (2003) showed that white mulch treatment led to higher populations of aphids than an unmulched treatment in summer squash.…”

Visual ecology of aphids—a critical review on the role of colours in host finding

“…The third strategy affected by the knowledge on aphid colour responses is the use of reflective mulches, although non-visual factors may also play a role in the effects observed (Dö ring et al 2004). In the investigations on the use of mulch for protection of plants from virus diseases, three features were often stated: (1) The higher the percentage of soil covered with mulch the higher the efficiency (e.g., Adlerz and Everett 1968;Lehmhus 2001); (2) The efficiency of the mulch decreases over the growing season along with the increasing canopy of the plant (e.g., Brust 2000); (3) The comparably high costs of mulching are only economically justified in high value crops or when severe losses occur regularly due to virus diseases (e.g., Brust 2000).…”