Since a few years tomato and eggplant growers get support from the predatory bug Macrolophus pygmaeus to control whiteflies. As this beneficial builds up its army slowly, it is important to introduce the bug early in the season. But once it is at full strength, it does not only protect the crop efficiently against whiteflies, but now and then it also likes to eat a spider mite, a moth egg or an aphid.
Macrolophus pygmaeus originates from the Mediterranean. There it often appears in greenhouses or tunnels where only few pesticides are used.
Macrolophus pygmaeus is a bright green predatory bug of 2 to 4 mm. It has red eyes and long green antennae with a black base. It has long legs with which it can move rapidly, even on leaves covered with glandular hairs. The female is a little bit taller than the male, and has a bigger abdomen with an ovipositor.
Three days after copulation the female deposits her eggs with her ovipositor in the tissue of the leaf, vein or stalk.
After 11 days at 25°C (77°F), or after 37 days at 15°C (59°F) nymphs are born. There are 5 nymphal stages. During the first stages nymphs are yellowish green, but older nymphs are bright green as the adults. In the last two stages the growth of the wings can be seen.
The five nymphal stages take about 19 days in total at 25°C (77°F), or 58 days at 15°C (59°F). So Macrolophus development is quite slow.
Female Macrolophus bugs live for 40 days at 25°C (59°F) or for 110 days at 15°C (77°F). Males live a bit longer. A female deposits in total between 100 and 250 eggs, depending on temperature and food. On a diet of only whitefly eggs more eggs are laid than when aphids or spider mites are eaten.
Although Macrolophus predates several pest insects, it clearly prefers whitefly, as well its eggs as its larvae and pupae. An adult can suck empty about 40 to 50 whitefly eggs per day. A punctured egg, larva or pupa can be recognised by a small hole where the bug has injected its rostrum. Sometimes empty preys are collapsed. Macrolophus eats both Bemisia and Trialeurodes.
As already mentioned above, Macrolophus also eats spider mites, moth eggs and aphids. Sometimes the bug suck plant juice. The activity of Macrolophus pygmaeus decreases when temperatures are lower and there's less light.
Macrolophus is used in tomato and eggplant greenhouses to control whiteflies in combination with the parasitic wasps Encarsia fomosa and Eretmocerus eremicus.
The first 3 to 4 weeks Macrolophus can hardly be found in the crop. It will take at least 2 months before a good Macrolophus population is built up. In this initial period the use of other beneficials against whiteflies (such as Encarsia formosa and Eretmocerus eremicus) is indispensable. After a few generations the Macrolophus population is at full strength to safeguard the crop against any unexpected infestations of whiteflies. Also for controlling other pests Macrolophus is an ally which should not be underestimated. For instance it is striking how the number of treatments against caterpillars in tomato has decreased since the use of Macrolophus. The Macrolophus nymphs are very appreciated for their contribution to the spider mite control.
Although Macrolophus may sometimes predate a whitefly larva that has been recently parasitized by Encarsia or Eretmocerus, this interaction does not have to be considered as negative. Both beneficials remain in the greenhouse, and will on their turn take up the main part of whitefly control depending on the moment or the situation.
If there is a lack of prey Macrolophus feeds itself with plant juices. Economical significant damage occurs only rarely.
Biobest presents Macrolophus per 250 and 500 pieces on vermiculite in a 125 or 250 ml tube. The bugs are all in the latest nymphal or adult stage. Macrolophus is best released in the whitefly hot spots or in warmer parts of the greenhouse, in sufficiently large piles, to make a population build-up possible.
Macrolophus can be stored for a short time at 8 - 10°C (46.4 - 50°F).
Not available in North and South-America!
Especially for spider mite control Biobest offers Macrolophus nymphs per 250 or 500 with vermiculite as carrier in a plastic tube.
Not available in North and South-America!
Note: Several pesticides have a negative effect on Macrolophus pygmaeus. Please be careful when controlling diseases and other pests. Consult Biobest's list of side effects of pesticides on beneficial organisms.
Macrolophus can exceptionally cause crop damage (such as poor fruit setting; flower drop; irregularly formed flowers, fruit or trusses; feeding spots on fruit) when the following conditions occur:
The greenhouse whitefly (Trialeurodes vaporariorum) is a typical greenhouse pest that affects many crops.
Tuta absoluta is a small leafminer belonging to Gelechiidae family (Order: Lepidoptera).
It causes economic damage, especially in tomato, with potential harvest losses up to 50-100% in untreated crops.
The Tuta larva pierces into leaves, stems and fruits. Also, secondary infections can occur at damaged sites.
This leafminer is also found in other ‘nightshade’ crops.
Tuta is native to South America. Since 2006 this species is also found in the Mediterranean, and recently in Western Europe.