Pineapple gub
| Pineapple gub | ||||||||||||
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Pineapple Lubricant ( Dysmicoccus brevipes ) |
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| Dysmicoccus brevipes | ||||||||||||
| ( Cockerell , 1893) |
The pineapple louse ( Dysmicoccus brevipes ) is a scale insect from the family of mealybugs (Pseudococcidae). Together with Dysmicoccus neobrevipes, it is one of the economically most important pests on pineapple plants .
features
The female adults have a plump and oval body shape and are light pink in color. The wax threads protruding on the sides of the body are about half as long as those that are directed backwards. The latter reach about half the body length. The females have a total of 17 pairs of these wax threads. The females look very similar to those of Dysmicoccus neobrevipes , which is why they were collectively seen as a two-breed species. It was not until 1959 that Beardsley realized that these were two separate species.
The adult males are about one millimeter long. They have eight antennae , which distinguishes them from the similar species that has ten. They have hairs that get a little thicker at the end, which also distinguishes them from Dysmicoccus neobrevipes , whose hairs don't get thicker at the end.
The larvae are the dispersal stage of the species. They have a flattened body with long hair that allows them to be drifted by the wind.
Occurrence
The pineapple grease louse is pantropically distributed over the entire tropics . You can also find them sporadically in the subtropics. The animals are particularly widespread in regions in which the pineapple is grown, such as the tropics of Africa , Australia , Central and South America , India and the Pacific region , such as Hawaii .
Way of life
The food plants of the animals are mainly pineapples and other bromeliads , but they can also be found on numerous other plant genera , such as on Annona , bananas , celery ( Apium ), citrus plants ( Citrus ), coffee ( Coffea ), cotton ( Gossypium ), milkweed ( Euphorbia ), Gliricidia , hibiscus ( Hibiscus ), mulberries ( Morus ), sedge ( Cyperus ), dendrobium and, unlike the related species, also on grasses.
The animals live mostly hidden at the base of the plants, such as the above-ground roots, the lower parts of the shoot axes and the fruit set in pineapple plants. This distinguishes them from Dysmicoccus neobrevipes , which live on the leaves, branches, flowers and fruits of plants.
development
The pineapple louse reproduces mainly asexually ( parthenogenetically ). For example, there are no males of the species in Hawaii, which is why the animals there can only reproduce through parthenogenesis. In places where both sexes occur, both one and the other mode of reproduction take place. The females do not lay eggs, but rather give birth to living larvae that have previously developed inside the mother. In the first 27 days the females do not give birth to any larvae, after which they lay an average of 234 offspring for about 25 days, the maximum number is about 1000. After that, they only live for about five days and die. The lifespan of an adult female varies between 31 and 80 days, with an average of 56 days. The life expectancy of pineapple bugs is between 78 and 111 days, on average 95 days. They go through three larval stages before they molt into an adult. The three stages last 10 to 26, 6 to 22 and 7 to 24 days, the average duration is a total of about 34 days. The larvae only eat in the first and the beginning of the second stage. At first they still live under their mother until their protective wax layer has developed.
Harmful effect
The species is an economically important pest on pineapple plants. The animals cause pineapple wilt, which makes the plants susceptible to saprobiotic organisms or causes them to dry up, can cause the base of the fruit to rot or interrupt the water supply to the inner leaves of the plant, which causes the leaves to change color in characteristic stripes. On coffee plants, the species is a rather insignificant pest that weakens the plants by sucking on the roots. Asterolecanium coffeae is the most important pest in coffee .
An important criterion for the spread of a pineapple bubbler colony and the associated damage is the presence of ants , which not only milk the honeydew that the animals excrete, but also defend the colonies against predators and parasites.
Natural enemies and combat
Natural enemies are a number of parasites living jewel wasps , such as Aenasius cariocus or Anagyrus ananatis or predators, like the ladybug Scymnobius bilucernarius , Scymnus unicatus or Scymnus pictus and gall midges as Lobodiplosis pseudococci . However, these cannot contain a strong infestation of mealybugs, as these are usually protected by ants.
In order to prevent an infestation of plantations, the ants are primarily fought. The edge of the fields is mowed so that ants can find little food and ant fences are put in place. Although these do not form a barrier against ants, they prefer to climb along the wire instead of crossing the fence. Finally, there is also the option of combating ants with pesticides. A field already infested with mealybugs must be cleared and plowed. All plants growing on it are burned beforehand.