Mealybugs

Mealybugs as pest and their control

1. Mealybugs Aqsa 684

2. Mealybugs (Classification) Kingdom: Animalia Phylum: Arthropoda Class: Insecta Order: Hemiptera Superfamily: Coccoidea Family: Pseudococcidae Genus: Planococcus Species: P.  citri

3. Introduction Members of scale insects Name is due to the sticky and powdery covering that resembles “cornmeal” 5000 species from 246 families of plants Waxy material, which protect them from loss of moisture and heat Common pest of indoor plants “Hard to kill insects” as they live in hidden places

4. Contd… Warm temperature favors their growth H erbaceous, woody plants, citrus plants and ornamental plants. Found all over world except Antarctica. Fruiting phase of plants Arboreal or subterranean. Can make colonies Suck plant sap.

5. Female Adult females are elongate, oval, soft Distinct segmentation 8–9 mm in length, Wingless Their thread-like mouthparts .

6. Male Adult male has a pair of long opaque wings Slender body Two multisegmented antennae that are about half the body length About 1.5 mm in length Active fliers & abortive mouthparts Only fly and find a female to mate

7. Commonly found types of mealybugs Rice mealybug Across East Asia, serious pest of rice in Asian countries . All stages except c rawlers infective. ii. Citrus mealybug Citrus plant pest. Female and nymph infective Greenhouse plants.

8. Contd…. iii . Long-tailed mealybug Possess long tail, 17 pairs of waxy filaments around periphery, (tail) filaments & bear young ones. iv. Root mealybug Present in roots. No filaments, serious pest of Africa violet.

9. Life cycle Stages of life Egg Oval, visible and are covered in ovisac. Color of eggs differ among different species & time of hatching. Nymph Instars are nymphal stages. First instars are called crawlers and active. Females have three instar and males have four for stages.

10. Adults Females develop after third instar . Parts and pores for secretion of wax . Not active, oval, pink to white in color and die after laying eggs hatch under the female’s dead body. Males are formed after fourth instar including pre-pupa and pupa stages. It is produced in cocoon. Three pairs of eyes and wing pads Active and pair of wings, lack mouth parts which means they do not feed. They are needed for mating .

11. Life cycle of P.citri Eggs are oval, yellow and glossy 300 to 800 in one. Hatching after 6 to 10 days. Nymphs appeared are coated with some wax particles containing red eyes. Instar are 4 in females while 3 in males (with pre-pupal and pupa stage). Males are in cocoon, greyish, contain wings and antennae, slender and elongated than females. Female grow completely in 6 to 8 weeks while male in 2 to 3 weeks. Females are wing-less and are coated with wax Total span is 30 to 35 days. Both males and females are almost equal

12. Damage Direct & Indirect plant growth, wilting, yellowing of leaves, leaf drop and possibly plant death Fungus; Indoor plants, green house plants Mango, banana and apple tree. Plants under irrigation or fertilization Affect xylem and phloem. Cotton mealybug in 2005, Sindh Punjab.

13. Contd… They secrete honey dew promote development of fungus creating a black sooty mass Honeydew flicked away by mealybug Mealybugs are carrier for various viral diseases and secrete toxins .

14. Methods of dispersal By planting of infected plants have cryptic behavior. Dispersal to distant areas can be due to trade of plants infected . Water used for irrigation is the source for Root mealybugs dispersal Air currents are responsible for spread of crawlers Instruments used for farming and harvesting used in infested area, if not cleaned properly may carry them. If natural predators are not present mealybugs spread rapidly. Ants are reported as an important source for dispersal of crawler

15. Control of mealybugs Chemical control They repel water soluble and polar insecticide due to their waxy coating . Controlled by some neonicotinoids ( dinotefuran) and systemic insecticides ( Azadirachtin ) or drenches . Can be applied in many ways Population above ground can be controlled by foliage cover spray.

16. Contd… Insecticide solutions applied to soil cause its penetration to root zone to control species underground. Applied through irrigation. Smearing of insecticides on stem and branches can also be done. Ethyl bromide fumigation can also be done

17. Insecticides Name Class Mode of action Acephate Organophosphate Acetylcholine esterase inhibitor Dinotefuran Neonicotinoids Nicotinic acetylcholine receptor disruptor Bifenthrin Pyrethroid Prolong opening of sodium channels Buprofezin IGR Chitin synthesis inhibitor

18. Oil Oils have long been used for the control of scale insects the integration of narrow refined oils with other insecticides was suggested as a means to dissolve the insect’s wax. Effective in the control of garden and household mealybugs. Neem oil and insecticidal soaps are used Not much effective on large area Neem Oil is also sprayed as insecticides

19. Physical control Water can cause mealybug’s flushing from leaves providing fast but temporary relief Colonies of mealybugs can crush and rub off by cloth. Removal of infested plants. Cleaning by cotton dipped into alcohol. Hot water is also an effective to get rid of mealybugs as it does not alter quality of fruit.

20. Biological control Cryptolaemus montrouzieri “Australian lady bird beetle” mealybug destroyer. Spalgis epius Indian butterfly, feed on root mealy bug .

21. Contd… Anagyrus pseudococci Parasitoids of citrus mealybug, . They feed of larval instars and females Anagyrus fusciventris Parasitoids, P. longispinus , One mealybug give birth to one wasp in about 3 weeks. They suck bodies of instars and kill them

22. Resistance in mealybugs Behavioral resistance Metabolic resistance Causes of resistance Waxy coating Cryptic behavior Presence of refugia Repeated exposure

23. Management of Resistance Different insecticide with different active ingredients should be used with planning i.e., rotation of insecticides. Insecticide should be sprayed accurately and at optimum timing. Only area infected with mealybugs should be sprayed. Biological control should be used rather than insecticide. Insecticide should be use in high volume as due to mealybugs wax coating and cryptic behavior they are difficult to kill.