Baiting European wasps: why bother? Merydyn Davison Insect Inquiries Officer Orange Agricultural Institute

Baiting European wasps: why bother? Merydyn Davison Insect Inquiries Officer Orange Agricultural Institute

European wasps European wasps like the same fruits we do. They have all day to locate and eat all they want. They can get to ripening fruit before we do.

European wasps They sting people and interrupt work. They kill some insect pests but they remove many invertebrates from the area around the nest, beneficials as well as non- target species. Baiting saves time and effort locating and physically treating a nest.

European wasps: Timing There are three perfect periods within their life cycle for baiting: Unfertilized queens looking for sugars to build fat in Summer and Autumn. Workers looking for protein to feed larvae, in late spring/ summer. Water stress during drought.

European wasps In late winter / early spring: Queens will fly when outside temperatures are above 12 degrees C but only in the warmest part of the day. A chance to reduce hibernating queens and small primary nests before larvae provide enough nutrition for the queen to increase egg laying.

European wasps Bait ingredients should suit the life stage of workers: Unfertilized queens love apples for fat deposition for hibernation and future egg laying. Workers love apples as fuel to power flight for foraging. Workers love meat to feed larvae. Meat can only be digested by larvae. Meat or liver is best liked as a large chunks.

European wasps European wasps have a genetic predisposition for apple which means baits are not attractive to other insect pollinators eg. bees or predatory wasps. Wasps will locate bait faster if they are in an area with a bait station.

European wasps Bait placement: Workers forage 200 m from the nest but will NOT leave the flight path for at least 20 m. Preferred nesting sites are creeks, dams embankments, logs, old rabbit burrows, houses and stored machinery. Place stations around these areas through out the year. Early detection means a problem free picking season.

European waps 6 to 8 week old nest produces 50 to 100 workers weekly. Foraging activities begin to be intensive and intrusive. Water-seeking behaviour in hot weather around watering points can create anxiety in animals and can cause injury.

European wasps Workers are not good at recruiting others to a food source. They need at least a day for nest mates to find the station. This means that pre baiting is very important. First place a station free of insecticide dust at the chosen site. When more workers visit the site, renew apple or meat and add dust in the evening. If wasp numbers are high, place a treated station within 2m of the original. Attaching the new station should be safe as it will take the wasps some time to find it.

European wasps How to make a bait station Requirements; 2 milk cartons String or tape for tying bait to stationary object eg. tree. Apple or meat Stanley knife.

European wasps: Bait station Measure 2 cm from base & draw a line on two sides of the carton.

European wasps: Bait station Once the first line is drawn, measure a second line 5 cm from base. Draw on two sides.

European wasps: Bait station Measure a point ½ way along the 2 cm line and then on the 5 cm line. Draw a line from one point to the other, within the two lines.

European wasps: Bait station Once the internal line is drawn, measure 1.5 cm (½ way point) along the middle line. Draw a dotted line from edge to edge. Measure 1.5 cm on dotted line from mid point.

European wasps: Bait station Draw a line from the 1.5cm point on the dotted line to the point on the 5cm line where the middle line meets. Complete the diamond on both sides of the carton.

European waps: Bait station Begin to cut out the diamond. Complete cut out on the second side of the carton.

European wasps: Bait station Take second carton: measure 7 cms from base. Draw line on all sides.

European wasps: Bait station Cut around line. Free standing ½ carton.

European wasps: Bait station Turn ½ carton on end. Dot out the folding lines on the carton base. Draw a triangle and cut out on 2 sides only.

European waps: Bait station On the base, measure 2cms from each side of the carton. Draw lines down to edge. Cut out middle section of carton on two sides.

European wasps: Bait station Freestanding base. Open top of carton.

European wasps: Bait station Slide free standing base down into carton.

European wasps: Bait station Slice the bottom off an apple and place on false floor. Fold down top. Once the station is secure, opening the top to check the quantity of bait left, is easy!

European wasps European wasps like to feed 1.5 m above ground. If tying the station to a branch, spray the area with a surface spray as wasps will not feed on anything which has ants on it. Ants also like liver, if that is the bait being used. The separation of dust and bait is very important as wasps don t mind walking through anything to get the preferred food. Mixing dust with bait changes the chemical profile of the bait and is unattractive to wasps. Once treated workers return to the nest, the colony will die within 24 hrs. This is a simple and time effective way of managing a difficult to detect pest.

European wasps Unfertilized queens do not follow worker rules. They are capable of flying 5 km in search of carbohydrates and many queens from different nests will happily share fruit. Home gardeners have reported more than 2 thousand queens per tree when there are no other trees in fruit.

European wasps Baiting throughout the year, when the temperature is right for flight, should be easy, not expensive and be capable of nipping infestations in the bud. The bait station can be a simple detection and elimination tool to ensure european wasps never reach damaging populations at any time of the year.