ANNONA

Name

Annona muricata

English name

Soursop

Name

Annona reticulata

English name

Custard apple

Name

Annona squamosa

English name

Sweetsop

Family

Annonaceae

Biopesticide category

Insecticidal Plants 

General

More than 90 species of small tree and shrubs are known in the Annonaceae family. They occur mostly in Tropical america, but some are found also in Asia and Africa. Soursop and custard apple are widely distributed in Central America and the Carribbean, while the sweetsop is commenest in India and Southeast Asia. They do not require special conditions of soil or water, but thrive best in places where there is a clear division between the rainy and the dry season, and generally prefer dry sites in which to grow.

The effective ingredients are in the unripe fruit, and in the seeds , leaves and roots.(107) The oil content of the seeds amounts

to 42-45 %.

 

Effective range

 

Contact - and stomach poison

Insecticidal , larvicidal , repellent , antifeedant. (52)

 

Target Insects

 

Aphids                               -  general (13)

Brown rice plant hopper  - Nilaparvata lugens (13)

Diamondback Moth         - Plutella xylostella (59)

Chrysanthemum aphid     - Macrosiphoniella sanborni (59)

Grasshopper                    -  general

Green bugs               -  general (13)

Green rice leaf hopper              -  nephotettix virescens (13)

Potato aphid                        -  Macrosiphum euphorbiae (59)

Red pumpkin beetle             -  Aulacophora foveicollis (59)

Whitebacked rice plante hopper - sogatella furcifera (13)

 

Annona has not proved effective against the

 

Saw-toothed grain beetle            Oryzaephilus surinamensis (147)

 

Trouver une photo de Sweetop (Annona squamosa)

 

Observations

 

The toxic effect of Annona sets in slowly , 2-3 days should be allowed.

Laboratory trials have shown that by extracting Annona seeds with ether or petroleum ether, the toxicity can be increased 50-100 times. But since laboratory methods are impractical in the field, other locally available and cheap solvents could be tried, like petrol or kerosene.

When pulverising the seeds of A. squamosa , care should be taken to ensure that the powder does not come in contact with the eyes as this causes great pain. (80)

The custard apple is the most effective of annonas against insects.

Trouver une photo de Soursop ( Annona muricata )

 

Methods of Use

 

Relatively little information exists on the preparation and use of Annona. Wide-ranging laboratory trials have demonstrated its highly effective insecticidal values. Experimentally-inclined farmers could contribute much needed information about widely distributed plant.

         A 10 % concentration of seed oil produces a 90 % death rate of the bug Urentius echinus within 72 hours. A 5-7 % concentration is still effective, but low concentration of 1 - 3 % produce no results.

         Pulverised seeds are used in China and the Philippines against Lecanium in West Africa. (68) The writers gives no details regarding quantities.

         An extract of the leaves with ether proves highly successful against the red pumpkin beetle (Aulacophora foveicollis). A diluted solution achieves a 91 % rate. (27)

 

CHILIPEPPERS

Name

Capsicum frutescens

English name

CHILIPEPPERS

Family

Solanaceae

Biopesticide category

Insecticidal Plants 

General

 

Chillies are widely distributed in the tropics and subtropics and originate in South America where they were early cultivated. They were introduced to the rest of the world by the Spaniards and the Portuguese. The ripe fruit has insecticidal properties and the effective substances are highest in the skin and in the seeds (47).

 

Effective Range

 

Stomach poison

Insecticidal repellent , antifeedant , fumigant , viroid. (52, 130)

 

Trouver une photo du chili  (Capsicum frutescens)

 

Target Organisms

 

Ants                                                          - general  (152)

Aphids                                                            - general  (152)

Caterpillars                                                   - general  (161)

Colorado beetle                                    - Leptinotarsa decemlineata (71)

Imported cabbage worm                                      - Pieris rapae (161)

Rice Weevil                                                      - Sitophilus  oryzae (41)

Warehouse pests                                           -  general  (52)

Cucumber mosaic virus                             (161)

Cucumber ringspot virus                             (161)

Tobacco etch                                                 (161)

Tobacco mosaic virus                                       (161)

Tobacco mosaic virus                                       (161)

 

Methods of Use

 

From Kenya good results are reported on the control of aphids in home vegetable gardens.

Hot chillippers are finely ground, stirred in water and allowed to stand overnight. After filtering through a cloth the solution is sprayed onto the plants , or if no syringe is available sprinkled with a whisk of twigs or grass. (152)

A similar method is reported from Papua New Guinea where chilipepper is used as repellent

Finally ground chillies are covered with water and soap either as flakes or liquid. The mixture is well stirred and sprayed over

affected plants (88).

Chilli spray preparation are also well known in the Philippines (130) :

100 g chillies, water, soap solution :

The chillies are finely pulverised in a mortar, vigorously shaken with 1 litre of water and filtered through a cloth. One part of this concentrate is diluted with five parts of soapy water before spraying. It is effective against aphids and many other vegetable pests.

Too strong a concentrate causes burning of the leaves, so the right strength should be found by testing.

Care should be taken because the solution irritates the skin (130).

 

Virus inhibition

 

MCKEEN reports that the young leaves of cowpea were rubbed with virus-infected sap expressed from chilli leaves the colour change was markedly reduced. Mostly there was even none. (The change of colour is regarded as an indicator of a virus infection). When the experiment was repeated with the sap from virus-infected tobacco leaves the cowpea leaves underwent a strong colour change, but when the tobacco sap was mixed with 5 % of chilli sap the number of leaves which changed colour was reduces by 95 %.

The effectiveness of the virus inhibition depends on the host plant. It is probable that members of the same plant family do not  work infallibly on one another virus inhibitors. Further tests showed that the virus-inhibiting ingredients is present in all parts of the chilli plant. However, extracts from the leaves and flowers showed the highest concentration and the roots are lowest.

In practise, it is important that chilli sap should be applied as a preventive measure before the virus infection affects the plant. Once the virus has taken hold it cannot be effectively controlled.

This is information is all derived from scientific sources. The writer has no results taken from practice in the field (96).

 

Chilli - Mixtures I

Effective sprays are often prepared from a mixture of different insecticidal plants.  

To control aphids a strong mixture of chilipeppers, garlic and onions can be made. The three ingredients are finely grated, stirred well with water and sieved. To increase the adhesive properties of the solution liquid soap should be added (161). The quantities used were not given by the contributor, so experiments should be made with different concentrations on small trials plots .

 

Chilli - Mixtures II

 

The following chillipepper/garlic mixture has a repellent effect on leaf-eating  pests : 

A handful of finely shredded chillis and garlic is well stirred in a litre of water, filtered and used as a spray. When no spray is available the liquid can be distributed by means of a bundle of grasses flicked over the plants. A spreader can also be manufactured from a tin by perforating it at the base (146).

 

 Chilli - Mixtures III

 

According to a source in the Philippines a mixture of the plant sap of chillipeppers, lemongrass and agdao leaves is very effective against insects. It is said that even the 'worst pests' of rice can be controlled with this preparation.

Each 5-6 tablespoons of the juice mixture from the three plants shouuld be stirred with 4 litres of water and shaken lightly before use. It was stated that 87 % of pests were killed with this preparation, but does not specify which (9).

 

Chilli - Mixtures IV

 

Rice farmers is Southeast-Asia use the following preparation against stem borers :

 

           Tubli roots (Croton tiglium)

           Dried tobacco leaves

                   Chillipepper

 

The tubli roots (no quantities given) chopped small and pounded, are mixed with 8 litres of water and the liquid reduced to half by boiling. 50 gm dried tobacco leaves are also mixed with 8 litres of water and also reduced to half by boiling.

4 tablespoons of grated chillipepper are stirred in 2 glasses of water and again reduced to half by boiling.

Finally all three liquids are strained and thoroughly stirred together. For the application 1 glass of this mixture is diluted with 15 litres of water (7).