Mealybugs are unarmored sap-feeding insects that you can find in places with warm and moist climatic condition. It is an insect from the family of Pseudococcidae and infests an array of greenhouse and house plants. It is a pest that sucks sap from plants and feeds on the plant juices as well as subtropical trees. It is also a carrier of many plant diseases. Usually, it makes a plant weak by secreting a sticky substance called honeydew, on the plant foliage. Gradually, the accumulation of honeydew develops into the formation of sooty molds.
Basic Facts about Mealybugs
They are found almost everywhere on the planet, excluding the polar regions. They can also enter into greenhouses and other structures in colder areas. They can be a real menace in warmer climates, and you may have to introduce mealybug destroyer to get rid of them. These insects try to live together in groups and can hide in the inner parts of plants like the leaf sheath, under loose bark, leaf axils or between twining stems. The excreta of mealybugs usually deposit on stems and leaves, and after it forms sooty molds on it, it can have a blackish appearance.
Citrus mealybugs are severe pests and can inflict some real, irreversible damage to plants. The other species of the insect can also damage grapes, coffee trees, ferns, gardenias, mulberry, orchids, sugarcane, pineapple, cassava, cacti, papaya, and sunflower. In some cases, people have also observed that the bug can infest carnivorous plants like Sarracenia or the Pitcher Plant. If such an infestation happens, it can be very tough to get rid of mealybugs, and you may have to apply insecticides like diazinon repeatedly. Moreover, the insect can be very much pronounced as a pest in the presence of ants because it tends to protect them from parasites and predators.
A small infestation of the insect may not always create significant damage. However, if the outbreak is large, it can even result in leaves dropping off! Lately, mealybugs have become invasive pests in urban areas also and cause some grave problems in the new age ecosystem.
In the following sections, we shall take a look into its lifecycle, some of the most potent varieties and the ways that can be employed to tackle them.
The Mealybug Lifecycle
The insect is sexually dimorphic, which essentially means that its two sexes have different characteristics – other than the difference in sexual organs. The males of the species are gnat-like smaller insects and have wings while the females look like nymphs. They do not have arms and show reduced morphology. In a mealybug lifecycle, the male mealybug may show massive changes developing from ovoid wingless nymphs to finally becoming wasp-type flying adults. However, mealy bugs are hemimetabolous insects as they do not undergo the full metamorphosis which usually takes place in insects.
Most species of the insect lay its eggs in a wax-like layer that it uses to protect them. The quantities range from 50 to 100. You can often find mealybug eggs in areas where the female of the species resides. There are some other species of mealybugs in which a mother gives birth directly.
In a mealybug lifecycle, the females usually live on plant sap which they find in other crevices and roots. In some cases, though, you can also see them in the bottom part of stored fruits. Generally, they stick themselves to a plant, and for protection, they secrete a powdery wax layer while enjoying the plant juice in ample amounts. The male of the species does not feed at all as adults, and their only aim is to fertilize the females. Therefore, these are short-lived.
Pink Hibiscus Mealybug
The Pink Hibiscus Mealybug has two common names- the hibiscus mealybug and pink mealybug. The scientific name of it is Maconellicoccus hirsutus, and it is a very severe type of pest. You can find it in many kinds of plants which grow in the tropical and sub-tropical regions of the world including but not limited to Southeast Asia, Northern Australia, and parts of Africa. In 1994, people noticed it in the Caribbean islands. Within the US, this species first made its way in Broward County, Florida on 13-June-2002. Later, people also found it in Dade County, and since then, it has only spread to other areas.
In Florida, the Pink Hibiscus Mealybug attacks various crops like citrus, carambola, guava, soursop, sugarcane, avocado, fig, and mango. It also infests many types of vegetables that include beans, cabbage, pigeon pea, lettuce, pumpkin, tomato, asparagus, beets, peanuts, cucumber, and pepper. It affects forest trees and many varieties of ornamental plants like Allamanda, Anthurium, Croton, Heliconia, hibiscus, oleander, Angelica, Bougainvillea, ginger lily, Ixora and palm.
Lifecycle of Pink Hibiscus Mealybug
A typical mealybug lifecycle includes females of the species laying eggs in winter in leaf scars, soil, within leaf and fruit clusters, under the bark and bark crevices, and tree boles. The reproductive rate is phenomenal as it can produce 600 eggs and has 15 generations a year. It dies shortly after laying its eggs. They deposit their eggs in egg sacs, and they look orange in color when they are fresh. However, before hatching, the color of eggs changes to pink. The baby crawlers that hatch out of these eggs get distributed by wind as well as by walking till they find their host plant. A typical life cycle of a Pink Hibiscus Mealybug is in the range of 24-30 days, but within the period, it can inflict massive damage.
Researchers found out the Citrus Mealybugs in 1913, and its scientific name is Planococcus Citri. It is a native of Asia but has traveled to the rest of the world including the Americas, Europe, and Oceania. It is fundamentally connected to citrus fruits but also attacks various types of crop plants, wild flora, and ornamental plants.
A female adult has a pink, brownish or white body. A layer of white wax covers it entirely. It measures about 3 mm long. It has longitudinal lines of light gray color down its back, and the edges of the body have waxy filaments. The antennae and legs are brown. In a Male, there are long wax filaments at the end of the body, and it possesses functional wings. It is comparatively more massive in size than the female and looks like a gnat.
Lifecycle of A Citrus Mealybug
In a mealybug lifecycle, a female lays heaps of mealybug eggs over plants. These heaps are known as ovisacs, and they cover it in cottony, fluffy layers of wax filaments. Each ovisac may contain up to 20 eggs which can be amber, pink or yellowish. The size of each egg is about 0.3 mm long. A baby mealybug of this family is very active and, is known as a crawler. It has a wax coating on its body. The eyes of a crawler are red, and its body is yellowish.
The life of an adult Citrus Mealybug banks on the temperature in which it lives. Females are known to survive for several weeks while males in an adult form live less than three days. A male mealybug does not feed during this time, and it only flies using its single pair of wings to find females for copulation. The women of the species are known to spend their time by feeding and producing eggs.
Damage Due to Mealybugs
A mealybug damage can be massive and quite substantial because they reproduce in hordes during their lifecycle. If you do not control a mealybug infestation in time, it can have disastrous consequences as large swathes of agricultural produce may get permanently damaged.
Mealybugs are a type of scale insects in which the female hides its eggs in fluffy white secretions. The eggs usually hatch in 10 days as nymphs which relocates to other parts of the plant and takes 4 to 8 weeks for developing into an adult. In the meantime, it sucks juice from its host plant and inflicts damage to it. It is also like many other pests, in the sense that it tends to like new growth. If it stays there for a considerable period, leaves may turn yellow and will finally drop off! Similarly, it can also cause a premature drop off for flower buds, vegetables, and fruits. If a mealybug infestation is massive, its waxy excretion will boost the production of sooty mold fungus.
Therefore, it is essential to find out about mealybug damage within the time so that you can take corrective action and control them satisfactorily.
Ways to Control Mealybugs
Mealybugs are serious pests which, if left unnoticed can inflict massive damage. However, if you take proper steps at the right time, you can quickly get rid of them. There are natural ways as well as a lot of mealybug insecticides which you can against it. We look here at some of the means of controlling them.
A mealybug destroyer is also known as Cryptolaemus or simply, Crypts. It belongs to the ladybug beetles group and is the most common natural enemy of mealybugs. Crypts are mealybug predators, and they lay their eggs in mealybug colonies. They hatch in 5 to 6 days at 81 degrees Fahrenheit. It has four larval stages with wooly wax appendages and looks a lot like mealybugs. Below the larvae, its real legs are hardly visible.
A real mealybug destroyer vs. mealybug battle starts from its larval stage when it starts feeding on the insect for around 12-17 days. In the larval stage, it grows beyond 1.3 cm. The pupae of the crypts stay in places like greenhouse structures or on stems. The adult Crypt comes out after 7 to 10 days, and they also like to eat mealybugs. The adults are dark brown and possess orange heads and tails. The adults can be up to 4 mm long. After mating, a female Crypt starts laying eggs within five days. it has a 50-days lifetime and can hatch 400 to 500 eggs in its lifespan.
The young and adult larvae like to eat Mealybug eggs while older larvae prefer eating any mealybug. Adult mealybug destroyers are capable of flying over vast distances as they have to do so in search of food. If there is no mealybug available in the vicinity, Crypts also feed on other insects like soft scales and aphids. A Crypt’s larvae can eat up to 200 o 250 small mealybugs. Hence, they are quite useful in keeping the pest under control.
If you are planning to use them for controlling purposes, employ 5 Crypts on an infested plant, or you can also use 2 to 5 Crypts in a square yard area. For an orchard, you can use 1,000 to 2,000 mealybug destroyers for an acre of mature trees. When the infestation is massive, they can be the most effective method of controlling mealybugs. You can also try releasing Crypts repeatedly so that an area becomes thoroughly sanitized of mealybugs.
If an infestation is found out, you may have to use mealybug insecticide to control them as Crypts may not be suitable for the purpose. Depending on whether you are producing vegetables or edible fruits, you can select a traditional pesticide or use something organic for controlling the menace. However, a natural solvent can be better suited as there will be no chemicals involved in it.
There are organic concentrate solutions that are well-suited to eliminate mealybugs, mealybug eggs and can also help in getting rid of fungus due to them. When there is a massive infestation, this type of organic solvent may be the best option.
In a lot of cases, fungus growth takes place due to mealybugs; the sooty black mold is the most common type. However, there can be other types of fungus also that can live with the insect. You can add 4 ounces of the solution in a litre of water that can take care of about 200 to 250 square feet area. It can be the most effective solution for houseplants, fruit-bearing trees and garden vegetables. Try using the same every week till you can see a perceptible change. Once you have destroyed them, use the process two times a month during the growing season, and you will be sure that there will be none left for a long time.
There are some very effective mealybug sprays which can be used to control the insect. They can be water-based as well as odorless so that you can easily use it in your yard plant or for any non-edible home purpose.
These types of mealybug sprays are usually slow-working, but that is due to the design of these products. Once you have spread them, their effect will start happening in 2 to 3 days when you can be sure that they have spread all over an area. You can easily use it on shrubs, plants, and trees. You can also use it as a foliage spray. It can also help in eliminating ants which depend on mealybugs for their honeydew. You can use a half ounce of a shower in a gallon of water and spray it over 500 to 1,000 square feet of a foliage area.
Some mealybug sprays are also helpful as a soil drench. If you use it in this way, plants and trees can absorb it within a few weeks and stay safe for long. Their effect usually lasts for at least a year so that if mealybugs do try to return, they will not be able to do so as they will get killed due to its effects. Try to make a tree drip line while spraying so that it can go through holes and create the best result. If you can use the spray in winter or during the initial parts of the spring season, plants will stay protected for the complete season.
Other options to control mealybugs
Apart from the ways mentioned above of getting rid of mealybugs, there are also some different ways of controlling them. In this section, we take a brief look at them.
1) If you notice mealybug infestation in a plant that can withstand cold, you can always try to place it on a windowsill during the colder season. The insect will try to conceal itself at the furthest leaves away from the window. You can wipe them off with a cloth.
2) Using Ladybird is also an option as the adults and larvae of the insect prefer feeding on mealybugs. You can use them effectively to control an infestation.
3) You can also use the fungus Lecanicillium lecanii to control mealybugs.
4) Some insecticidal soaps are there that are very effective against the insect. You can readily get them online and also at many stores.
5) If there is a symbiosis of mealybugs with ants, you can try using Diatomaceous earth. It has small silica particles in ant’s joints. It irritates and finally leads to them to death.
We can understand here that mealybugs are potent pests and can damage a whole area if infested. Therefore, it is essential to understand the morphology and all details of this insect so that you can take preventive steps. If you take a useful measure at the right time, you can easily control a mealybug infestation.