Crymo, or Cryptolaemus montrouzieri, is an Australian species of predatory beetle in the same family as ladybugs. They resemble the ladybugs we know and love, but the adults are black in color. They are about 4 mm long as adult beetles. Crymo has a strong appetite for mealybugs, so much so that their common name in English is the mealybug destroyer!
Life cycle of Cryptolaemus / Crymo
Females lay about 10 eggs per day, which causes white larvae to appear after a while. These larvae can reach 13 mm in length and are covered with waxy white appendages, which at a very young stage gives them the appearance of the scale insect. The beetle and its young larvae prefer to eat the eggs and young larvae of the mealybug. The larger larvae are fond of all larval stages of its prey. The larvae eat more than the adults and are therefore the most important mealybug eaters.
When to use Cryptolaemus?
For a good oviposition and development of the larvae, a temperature of 22 to 25° C and a high humidity of 75 to 80% are necessary (mist the plants regularly). If the humidity is low, you can't count on the offspring and will have to anticipate that with the purchased generation, you will solve your problem. Cryptolaemus can therefore only be used indoors or in greenhouses. At temperatures below 16°C, the beetle will go into lethargy (diapause). Temperatures above 33°C disturb the beetle's foraging behavior and should be avoided. Cryptolaemus therefore requires specific conditions to function properly. With little mealybug, the beetle does not lay eggs because there is too little food for its offspring. Cryptolaemus is used when there are many mealybugs. Ants in plants can have a negative effect on the functioning of Cryptolaemus. Ants like the honeydew of mealybugs and protect them from predators.
How many?
The number depends on the extent of the mealybug invasion. Usually 3 to 5 larvae per m² are released. Place the larvae in the immediate vicinity of the mealybug outbreak. Open the cap of the bottle and sprinkle them on the affected plants. Since we deliver Crymo larvae and not adults, they cannot fly away from the plants.
Crymo temperatures
Cryptolaemus can only be applied at (night) temperatures above 15°C. The larvae are available year-round. However, if you want to control mealybug at low temperatures, use Chrysopa. Chrysopa larvae are also very good mealybug eaters and are not temperature and humidity dependent, making them much easier to use in some situations.
Mealybugs outdoors
Woolly aphids are often mistaken for mealybugs outdoors. This insect is not controlled with Cryptolaemus but with Chrysopa. Chrysopa fights both mealybugs and aphids.