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close this book Calliandra calothyrsus - Production and use: A Field Manual
View the document Preface
View the document Acknowledgments
View the document 1. Botany and Ecology
View the document 2. Seed Collection and Production
View the document 3. Establishment
View the document 4. Uses
View the document 5. Fodder Production
View the document 6. Pests and Diseases
View the document Seed and inoculant suppliers
View the document Authors
View the document Selected References
View the document Morphological and seedling keys to the identification of species in the Racemosae.

6. Pests and Diseases

Eric Boa

Calliandra species do not appear to suffer serious damage from pests or diseases, either in their native range or in areas where they have been introduced. This suggests that farmers and local communities will be able to expand their use of these trees with little risk of pest or disease problems.

This general observation calls for a word of caution, however. There has been very little systematic study of pests or diseases in Calliandra species. Field observations have been limited and sporadic, and proper scientific assessment has been rare. This reflects the marked absence of suitably trained tree disease specialists in many developing countries. Given our incomplete knowledge of present pest and disease problems, we have a weak basis on which to calculate future risk—particularly in view of increased plantings and the widespread use of improved varieties.

Table 1 summarizes the information available on fungal diseases, Table 2 summarizes information on insect pests, and Table 3 gives information on other disease conditions, mostly resulting from unknown causes. These tables draw on two recent lists of pests and diseases affecting members of the genus. The first major attempt at a comprehensive listing appeared in Lenné (1990). In 1992 and 1993, Jill Lenné and 1 conducted field surveys of pests and diseases in natural populations of Calliandra spp., Leucaena spp., and Gliricidia septum, work supported by the Forestry Research Programme of the UK Overseas Development Administration. Within Calliandra we concentrated principally on C. calothyrsus.

The final report of this project contains detailed observations of diseased specimens, selected colour photographs, and an assessment of the economic and quarantine significance of the diseases observed. For copies, contact me at the address given above. The results were later included in a general publication covering diseases of nitrogen fixing trees in developing countries (Boa and Lenné, 1994), which has also been consulted for this account of Calliandra pests and diseases. I have also searched the CAB International TREE CD, a compilation of all the abstracts published in Forestry Abstracts from 1939 to the end of 1995.

Smith and Vanden Berg (1992) have prepared a useful booklet with excellent colour photographs of leaves showing symptoms of idiopathic conditions and nutrient deficiencies. These are not specifically referred to in this account.

Suggestions for diagnosis

One problem for farmers or community workers introducing or expanding the use of Calliandra species is that symptoms such as dieback, loss of leaves, and general failure to thrive are nonspecific. Such symptoms may occur as the result of adverse growth conditions related to climatic conditions, water availability or the tree site, and are not necessarily indicative of pest attack. Carefully observe the distribution of leaf drop and dieback within the crown since this will give an initial indication of the possibility of pest attack.

Other symptoms of pest attack are less equivocal. Rapid wilting, for example, results in a distinctive "burnt" appearance of the foliage. Canker development and leaf spots are also reliable indicators of pest attack. The presence of large numbers of insects may provide clear evidence of what is causing observed damage. There is a tendency to assume that large and visible insects are pest organisms, but you need to be aware that insect pests are not always readily found in association with the damage they cause.

Tree management practices can make diagnosis difficult because of the removal of diseased parts. Branches and foliage may be cut because they are diseased or showing poor growth, but removal more usually occurs to meet routine needs for tree material. In my experience, farmers have a poor awareness of tree diseases. Seasonality of growth and variation in the appearance of foliage and extent of leaf cover is another important factor in assessing the health of trees. Foliage and crowns generally usually appear much less healthy at the end of a dry season than during periods of active growth. Accurate assessment of tree health thus relies on a familiarity by observers of routine tree management practices and seasonality of growth. This emphasises the need to monitor trees at different times of the year and to discuss tree health issues with farmers.

The range of pest organisms listed in Table 1 suggests that the most common symptom is leaf damage of some sort. A number of rust fungi have been observed on Calliandra, although none has been recorded causing significant damage. These fungi have a typically powdery appearance, occurring as small raised dots, usually on the underside of leaves. They may be inconspicuous and thus easily missed. There is no evidence that they cause damage to stems and other parts of the tree.

In some areas intensive coppicing of C. calothyrsus is associated with increased damage by Corticium salmonicolor, or 'pink disease', a widespread pathogen attacking many woody hosts; the stumps are also attacked by Xylaria sp.

Dieback has been observed in association with fungal attack, but there are only two examples of a root rot and the only one other example of pink disease. This causes a general blight and may also result in limited canker formation. There are no recorded wilts affecting Calliandra and no evidence of either viral or bacterial diseases. Minor leaf damage often results from inconsequential insect feeding: this is usually revealed as a series of specks on the upper leaf surface.

Assistance with diagnosis

It is always best to ask a local pathologist or entomologist to help diagnose a tree disease problem, but the International Mycological Institute operates a disease diagnosis and fungal identification service for situations where trained specialists are not available locally. Readers are encouraged to send their questions on disease problems, along with samples, to the author—Eric Boa, Tree Health Specialist, at the International Mycological Institute, Bakeham Lane, Egham, Surrey TW20 9TY, U.K (e.boa@cabi.org). Examination of diseased material is undertaken for a modest fee. Reduced charges apply to many developing countries and charges may be waved, depending on the country and institute requesting assistance. Further information is available from the author. Advice can also be given on identification of insect and nematode pests through services available from other CAB International scientific institutes.

When sending plant material for diagnosis, leaf samples are best pressed lightly to ensure that the leaves dry quickly and to preserve any fungal structures. Note that Calliandra leaflets or pinnae start to curl almost immediately after branches are cut, at least for C. calothyrsus and C. houstoniana, so have suitable pressing facilities readily on hand. Branches that are dying or show evidence of localized necrosis should be sampled at the junction between healthy and diseased tissue. Never wrap samples in polythene or plastic bags because samples will rot. Small insects can be preserved in 75 percent alcohol in sealed tubes. Insect larvae are less useful than adults for identification purposes.

Make sure that you provide detailed notes concerning the condition of the tree and where it is growing, and give each sample a unique code or number. In addition to specimens, photographs of symptoms are extremely useful.

Table 1. Fungal diseases of Calliandra spp.

Information is from Boa and Lenné (1994) unless otherwise stated.

Disease

Fungus species

Host species

Occurrence

Symptoms and notes

Black mildew

Asteridiella sp.

C. calothyrsus

Belize, Mexico

Minor pathogen; black pustules commonly seen on upper surface of leaves

   

C. houstoniana

(probably widespread in Central America)

 

Dieback

Nectria ochroleuca

C. surinamensis

Sierra Leone

-

Dieback

Nectria rigidiuscula

C. surinamensis

Sierra Leone

-

Dieback

Thyronectria pseudotrichia

Calliandra sp.

   

General blight

Corticium

C. calothyrsus

Papua New

-

("pink disease")

salmonicolor

C. surinamensis

Guinea

 

Leaf drop and dieback

Camptomeris calliandrae

C. calothyrsus

Honduras, Costa Rica

Associated with moderate to severe damage on C. calothyrsus in Honduras; forms powdery pustules on lower surface of leaves, superficially resembling rust, but spores easily distinguished; no information on disease in Cost Rica, but could be more widespread

   

C. surinamensis

   

Leaf mould

Cladosporium sp.

C. surinamensis

Costa Rica

Unlikely to be associated with any primary damage to foliage

Leaf spot

Cercospora sp.

Calliandra sp.

USA

-

Leaf spot

Helminthosporium sp.

Calliandra sp.

USA

-

Pod scab

Sphaceloma sp.

C. houstoniana

Mexico

Produces rust coloured pock marks on pods that could easily be overlooked or confused with insect damage; only seen at one site in Palenque, but probably under-recorded; major disease on other legumes; occurrence on pods raises quarantines issues

Leaf spot

Helminthosporium sp.

Calliandra sp.

USA

-

Pod scab

Sphaceloma sp.

C. houstoniana

Mexico

Produces rust colouredpock marks on pods that could easily be overlooked or confused with insect damage; only seen at one site in Palenque, but probably under-recorded; major disease on other legumes; occurrence on pods raises quarantines issues

Root rot

Ammillaria mellea subsp. africana

C. calothyrsus

Kenya

Limited outbreak of root disease at cooler high altitude sites; also affected Jacaranda mimosolia and Grevillea robusta; trees were killed (Paterson & Mwangi, 1996)

Root rot

Ammillaria tabescens

Calliandra sp.

USA

-

Rust

Ravenelia affinis

Calliandra sp.

Brazil

-

Rust

Ravenelia armata

Calliandra sp.

Brazil

-

Rust

Ravenelia bizonata

Calliandra sp.

Guatemala

-

Rust

Ravenelia dieteliana

Calliandra sp.

Brazil, Taiwan

-

Rust

Ravenelia echinata

Calliandra sp.

Ecuador, Mexico

-

Rust

Ravenelia echinata

C. calothyrsus

Costa Rica, Guatemala, Mexico, South America

Pustules inconspicuous; var. ectypa not associated with any notable damage to foliage in Guatemala; no information from other countries

Rust

Ravenelia lagerheimiana

Calliandra sp.

Mexico

-

Rust

Ravenelia mexicana

C. houstoniana

Guatemala,

 
   

C. jazepzukii

Mexico

Inconspicuous pustules; not associated with any significant damage

Rust

Ravenelia pazschkeana

Calliandra sp.

Brazil

-

Rust

Ravenelia reticulate

C. humilis

Mexico

-

Rust

Ravenelia spp.

Calliandra sp.

Honduras,

 
   

C. houstoniana

Guatemala

Sample from C. houstoniana in Guatemala associated with significant leaf loss and general blight; difficult to identify Ravenelia species when teliospores absent

Rust

Ravenelia texensis

Calliandra sp.,

USA

-

   

C. humilis var. reticulata

   

Rust

Ravenelia texensis var. texensis

C. humilis

Mexico, USA

-

Rust

Uredo longipedis

Calliandra sp.

Brazil

-

Rust

Uredo quichensis

C. conzatti

Guatemala

-

Sooty mould

Periopsis fusispora

C. tweediei

Trinidad

Unlikely to be associated with any primary damage to foliage

Stem blight

Phomopsis sp.

C. tweediei

Cuba

-

Stump rot

Xylaria sp.

C. calothyrsus

-

-

 

Table 2. Insect pests of Calliandra spp.

Insect species

Host species

Occurrence

Symptoms and notes

References

Leucopholis irrorata

C. calothyrsus

Philippines

Scarabid beetle recorded from a growth plot in uriago del Sur

Braza (1991)

MyIIocerus viridanus

Calliandra sp.

India

Common teak defoliator also noted on other herbs and trees; capable of causing significant defoliation

Mukhtar-Ahmed & Ahmed (1989)

Pachnoda ephippiata

C. calothyrsus

Kenya

Rose flower beetle; infestation aggravated by prolonged dry spells

Kaudia (1990)

Sabyadrassus malabaricus

C. calothyrsus

India

Teak sapling borer also attacks other young trees

Nair (1982)

Spittlebug ("salivazo")

C. calothyrsus

Central America

Unidentified cercopid (plan/hopper); no specific information

Hilje et al. (1991)

Stator sordidus

C. calothyrsus

Nicaragua

Bruchid beetle; attacks seeds

Johnson & Lewis (1993)

Stator limbatus

C. calothyrsus

Nicaragua

Bruchid beetle; attacks seeds

Johnson & Lewis (1993)

Stemborer

C. calothyrsus

Philippines

Noted as resembling Hypsipyla robusta (mahogany shoot borer)

Luego (1989)

Tetraleurodes acaciae

Calliandra sp.

USA

Acacia whitefly; no information on damage; probably found only on ornamental Calliandra

Johnson & Lyon (1994)

Tussock moth

C. calothyrsus

Philippines

Unidentified Iymantrid also recorded from growth plot in Suriago del Sur

Braza (1991)

Umbonia crassicomis

C. calothyrsus Calliandra sp

Guatemala, Central America, USA

Distinctive thorn bug with red tip to prominent spine; no specific information given on damage to tree; Boa noted in Guatemala; probably widespread though rarely causing significant damage

Hilje et al. (1991),. Johnson& Lyon (1994)

 

Table 3. Other disease conditions of Calliandra spp.

Condition

Host species

Occurrence

Symptoms and notes

References

Parasitic plant(Struthanthus quercicola)

C. calothyrsus

Central America

No information

Hilje et al. (1991)

Leaf and stem galls

C. calothyrsus

Honduras, Guatemala

Frequently seen but more of biological curiosity then disease significance; presumed to have an insect cause but no association positively identified

Boa and Lenné(1993)

Flower blight

C. calothyrsus C. jazepzukii

-

Dieback of floral stalk; flowers appear to die prematurely and become covered in secondary black mould; gummosis seen occasionally

Boa and Lenné(1993)

Seed rot

-

-

Seeds die in pod; similar to bacterial pod rot in Leucaena (caused by Pseudomonas fluorescens) but no bacterial association proven

Boa and Lenné(1993)