FAO Plant Protection Bulletin - Notes on Some Mealybugs (Coccidae) of Economic Importance in Ceylon - Summary of research

Oct 13, 2026

Upload by Asher

Report presents FAO-supported entomological studies on mealybugs (Coccidae) of economic importance in Ceylon, carried out in 1953 as part of an FAO project. Experiments address cacao virus transmission, experimental confirmation of mealybug wilt of pineapple, and establishing PseM-dococcus as the causal agent of kapok seedling malformation. Methods include controlled transmission trials using infected mealybugs on cacao beans and inoculation of pineapple plants with gravid females on leaf sections, with observations of symptom development and practical implications for control.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages13

Reading Time33 min

AccessFree to download

Cacao Virus

Disease diagnosis and experimental transmission

Vector role and conclusions

Mealybug Wilt of Pineapple

Distribution and conditions favoring disease

Experimental confirmation of diagnosis

# FAO Plant Protection Bulletin Notes on Some Mealybugs(Coccidae)of EconomicImportance in Ceylon WALTER CARTER¹Entomology Department,Pineapple Research Institute,Honolulu,Hawaii HE Coccidae or seale insects of Ceylonwra tha anhiont of a naur laaaioolwere the subjeet of a now classicaltaxonomie treatise by Green (3).This reportcovers studies on the economie importance ofseveral species of mealybugs,undertaken aspart of an FAO project,in the EntomologySection,Department of Agriculture at Pera-deniya in 1953. Included are the results of experiments onthe transmission of cacao virus,the confir-mation of a previous diagnosis of mealybugwilt of pineapple by experimental mealybuginfestations and the establishing of a PseM-dococcu88p.as the cause of a malformationof kapok(Ceiba pentandra)seedlings. Cacao Virus Cacao virus disease was first noted in1949 by J.W.L.Pieris of the Ceylon Depart-ment of Agriculture,who submitted leavesshowing the typical oak-leaf pattern to A.F.Posnette,then of the West Afriean CacaoResearch Institute,for diagnosis.²Posnetteconfirmed Pieris'opinion that the symptomswere similar to a strain of swollen shoot inWest Africa.Although my own experiencewith the swollen shoot disease complex waslimited to a few months spent as a member of the Swollen Shoot Commission,the leafsymptoms as observed in the Peradeniya areawere typical of those seen in West Africa,although the rounded fruit was seen only once,and the swelling of the stems not at all.Theleaf symptom is a striking oak-leaf pattern(Figure 1). In view of the diagnoses on the basisof leaf symptoms,the known role of mealybugsas vectors,and the frequeney of mealybuginfestation on eacaoinCeylon,the necessity forthe testing of these mealybugs was clearlyindicated. Three species of mealybugs were foundon eacao.Of these,Pseudococeus lilaeinu8(Cockerell)was by far the most common.P.citri(Risso)and Ferrisia virgata(Cockerell)were found only on occasion,the latter beingalmost invariably as8ociated with the flowerpads on the tree trunks. The technique of transmission was essen-tially that described by Posnette(4)with amodifieation that eliminated the dissectionof the bean.The latter resulted in too higha percentage of rotted beans under the localconditions for growing the seedlings.Beanswere washed elean and set in large Petridishes on moist paper.Large numbers ofmealybugs from diseased trees were thenintroduced into these dishes and a fair pro-portion settled on the beans.From twoto four days later,the beans were planted inflats and grown in a large sereened eage. Using this technique,positive resultswere obtained with Pseudococeu8 lilacin₈8 Figure 1.Cacao leoves showing the typical ook-leofpattern of swollen shoot disease. and P.eitri.Experiments with Ferrisiavirgata were inconclusive up to the time Ileft Ceylon.In the positive cases,the firstsymptom was vein-clearing,which developedin approximately two month8.The typicaloak-leaf patterns developed on later flushes. The experimental results made it clearthat mealybugs are the vectors of cacao virusin Ceylon,and indicate equally clearly thatthe virns is closely related to the swollenshoot complex of West Africa.In theabsence of comparative yield records,nopositive estimate ean be made of the debili-tating effects of the virus disease on the treebut from observation in the field on the vigorof infected trees,it seems likely that thedisease is actually a mild one.Sickle-leaf(a deficieney disease),the activities of Helo-petis,and black-pod disease(Phytophthorapalmivora)are probably of far more economieimportance.Even granting this to be true,however,control of eacao virus is desirable.Fortunately most of the cacao plantingsin Ceylon are plantation style and except for extremely hilly locations,lend themselvesin some degree to mechanical spray controlmethods.Formieidal sprays could well becombined with sprays against Helopeltis andwith suitable formulations effective againstblack-pod diseas

FAQs

What FAO project topic does the bulletin address?

It studies mealybugs (Coccidae) with economic importance in Ceylon, including their role in plant diseases under an FAO project in 1953.

How was cacao virus transmission tested in the experiments?

Cacao virus transmission was tested by placing large numbers of mealybugs from diseased trees onto cacao beans in Petri dishes, then planting the beans and observing development of symptoms.

What was the purpose of the pineapple mealybug wilt experiment?

The experiment aimed to confirm the diagnosis based on symptoms by infesting healthy young pineapple plants using gravid Pseudococcus brevipes females reared on leaves from apparently normal plants.

Oct 13, 2026

Upload by Asher