Surveys

The first phase of the work consisted of surveys, in the 3 regions of northern Ghana, in order to gain a better understanding of the situation: the extent of the damage caused by the pest, and the ways farmers cope with the problem.

Damage caused by the pest

The following chart represents the average damage recorded on stored cowpea in the Northern Region during the storage season 96-97. 35 farmers were visited over the season, and their cowpea was sampled monthly. The number of farmers decreased over the storage season as they sold or consumed their cowpea: few farmers keep their cowpea in store over the entire storage season.

% damage over the storage season, and number of farmers still storing

Percentage damage is the number of cowpea beans with at least 1 bruchid hole, out of 100 beans.

Imposed storage duration

When farmers were asked to keep their cowpea in storage over the whole season, some experienced heavy losses, with damage reaching 90%. The following chart displays the damage for each individual farmer.

% damage recorded in individual farmers' stores

Survey of control methods: traditional and modern

Farmers were asked which control method they use against bruchids when storing cowpea.

This survey was undertaken in the Northern (NR) and Upper East (UER) Regions of northern Ghana:

 

Treatment

Region

Mean % damage

Number of farmers

Cypermethrin / sun dried

NR

66.2

1

Phosphine / Cypermethrin

NR

60.1

1

Cypermethrin

NR

45.3

8

Sumicombi (Fenitrothion + Fenvalerate)

NR

44.5

4

sun dried

NR

40.5

1

not treated

NR

36.2

9

Cypermethrin / Sumicombi

NR

36.0

2

Napthalene

NR

23.4

2

Phosphine

NR

17.4

5

Mix with ash, no heat: heated over fire later

UER

7.8

1

Mix with ash

UER

7.4

2

Heat over fire and mix ash

UER

6.2

31

Heat over fire and mix ash and orange peel

UER

3.5

1

A similar survey was undertaken on another traditional legume, the bambara groundnut, which is also attacked by bruchids during storage. Many more traditional methods of control are used on bambara nuts:

Type of treatment

Treatment

Region

Mean % damage

Number of farmers

Not treated

-

NR

6.0

12

-

UER

4.5

1

Actellic

2% dust

NR

16.7

1

(Pirimiphos methyl)

25% emulsifiable concentrate

NR

9.1

1

Dry materials

Mixed with wood ash

UER

3.4

2

mixed

Mixed with ash and kul-enka

UER

2.1

1

Kimkim mixed with seed

UER

0.9

2

Water based

Immerse in warm water

UER

5.7

1

ash

Immerse in ash in warm water

UER

1.4

1

Steamed ash in water, pored over bambara, dried

UER

1.3

3

Immerse in warm water, dry, mix in ash

UER

0.6

3

dawadawa

Dawadawa seed boiled in water, poured over grain

UER

10.7

3

Dawadawa seed boiled in water, poured over grain, coat with ash

UER

0.1

1

Dawadawa seed and kimkim boiled in water, poured over grain

UER

3.2

1

kimkim

Dipped in boiled kimkim water

NR

2.5

12

Immerse in kimkim boiled water

UER

6.4

5

Immerse in kimkim and neem leaves boiled water

UER

26.5

1

Immerse in kimkim boiled water, dry, mix with ash

UER

1.2

2

Immerse in kimkim boiled water, dry,

UER

0.6

5

shea butter

Soak in shea butter waste water

NR

2.0

6

Immerse in water in which shea butter dissolved

UER

1.6

2

neem & orange peel

Added orange peel to water with neem

UER

0.0

1