PESTS AND DISEASES ASSOCIATED WITH

AMARANTH

By

GABRIEL WANYONYI SHIKUKU

REG. A138/10130/2007

SUPERVISOR: DR KIMENJU

INTRODUCTION

• Amaranthus or pigweed, is a cosmopolitan genus of herbs.

• leaves are long-stalked with prominent whitish veins.

• flowers vary depending on species.

• people around world value amaranths as vegetables, cereals and ornamentals.

• Its nutritious leafy vegetable rich in amino acid lysine, vitamins and mineral salts

Introduction cont

• Due richness in macro and micro nutrients

• Its used to address health problems in the

society.

• Integration its grain in the daily diet can

help children recover from malnutrition

1.0 Amaranth Production in

Kenya

• In Kenya, its a minor crop grouped under indigenous vegetable.

• It s grown and consumed in many parts of the country.

• production was mainly localized to Western and Nyanza provinces.

• Production is Kenya is mainly rain fed and subsistence.

its intercropped with main crops or grown on small areas near households.

1.2 Constraints and Future

Prospects of Amaranth

• it is known to contains anti-nutritional factors

such as oxalic acid.

• Small seed size has been documented to pose

limitations in planting, harvesting, threshing and

cleaning.

• Lack of quality seed and technical information .

• Diseases eg Rhizoctonia spp. Phytophthora spp.

Fusarium spp. & Pythium spp

• Pests eg aphids,caterpillars & leaf miners

1.3 Problem of statement and

Justification

• Amaranth represents the largest source of nutrients of all the vegetables and grain.

• Grain and vegetable amaranths have potential to provide many nutritious foods.

• Amaranthus has alleviated problems of malnutrition in developing nations

• Pests and diseases cause reduction on yield and quality of the crop.

• to attain commercial production , there is need to identify and check factors limiting production such as pests and diseases.

1.4 Objectives

• Main objective of this study was to

document the pests and diseases of

amaranth & record the relative proportions

(incidences) with which they occur.

• Specific objective was to establish the role

of weeds in the occurrence of pests and

diseases on Amaranth.

MATERIALS AND METHODS

• Experiment was conducted at the University of

Nairobi farm, Upper Kabete field station.

• Four races {Race 1, Race 2, Race 3 and Race 4] of amaranth seeds were planted in 2x2m plots.

• Experiment was arranged in a split- plot design with Amaranth races as the main plot and weeded/non-weeded treatments as subplots with four replications.

• Disease incidence was scored for using a scale

and diagnosis was done symptomatically

Material $ method cont

• Data on disease incidence was collected weekly.

• For unknown diseases, Kochs postulates was done.

• Data on pest count was collected on five plants tagged randomly.

• Counts on beneficial insects were also done.

• Assessment for pest damage was done by scoring for the number of plants damaged in each treatment.

• Nematode population in soil and root tissue was estimated using Modified Baremann technique .

4.0 RESULTS

• 4.1 Effect of weed on aphids

• Significance Difference along the rows

were observed between the weeded and

non wedded plots (P 0.05).

• aphids population were more in the non

weeded plots in all the races compared to

weeded plots

Table 1.0 Mean aphids population

Races

Weeding No

weeding

R1 2.25 2.56

R2 0.25 0.5

R3 2.25 2.5

R4 3.0 2.75

LSD 0.24

4.2 Effect of weeds on caterpillar

population

• Weeds control had a significance

difference on reduction of caterpillars on

R1,R3.

• No difference on R2 and R5 although

wedding cleared all the caterpillar on R2.

• No difference among the four races

Table 2. Mean of caterpillar count.

Races

Weeding No

weeding

R1 0.25 0.75

R2 0.25 0

R3 0.4 0.75

R4 0.5 0.75

LSD 0.3

4.3 Effect of weed on ladybird

beetle

• Significance difference (P 0.05)was

observed on R3,R4,.

• no effect on lady bird after weeding on R1

and R2.

• there was reduction of ladybird. Table 3.

Table 3. Mean count of lady bird

Races

Weeding No

weeding

R1 6.25 6.30

R2 5.5 6.0

R3 5.0 7.0

R4 6.5 8.0

LSD 1.05

4.4 Effect of weeds on leaf beetle

• Weeding significantly reduced leaf beetle

on amaranth’s especially on R2 (Table 4.).

• There was no significant effect on the

other three races even after weeding.

• Race 2 had highest leaf bettle observed

compared tho other plots with other races.

Table 4 Mean count of leaf bettle before and after weeding

Races

Weeding No

weeding

R1 1.53 1.5

R2 125.93 23.35

R3 0.25 0.48

R4 0.25 0.25

LSD 0.63

4.5 Effect of weed on bacterial

diseases

• Weeding was observed to have

significance effect on bacterial diseases (P

0.05).

• The greatest reduction of diseases was

observed on R3.

• The least ON R2 where there was no

significant difference.

Table 5.0 Mean Bacterial disease score on weeded and non weeded plots.

Races Weeding No

weeding

R1 26.75 22.0

R2 0.25 0.5

R3 26.25 24.7

R4 34.25 30.0

LSD 2.45

4.6 Effect of weeds on viral

diseases

• Viral disease were low during the project period example in R2,R3 & R4.

• There was a significance difference between weeded and non weeded plots in R2.Table 6.

• no significance was observed between the races which may be attributed to the low disease score.

Table 6. Mean viral disease score in weeded and non weeded plot

Races Weeding No

weeding

R1 0.0 0.0

R2 25.0 19.05

R3 0.0 0.0

R4 0.0 0.0

LSD 0.934

Discussion

• Amaranths was found to have many pests and

diseases.

• The experiment result had shown that weeding can reduce the pest population and diseases incidence.

• Reduction of pest population on weeded plots can be explained by the fact that some weeds may harbors pests and can act as alternative crops for pests

• Weeding simple practices can be used to minimizes diseases and pests.

Conclusion .

• Amaranths being an important crops has

shown to be preferred by many pest like

caterpillars, aphids, leaf beetle among

others.

• Bacterial and viral diseases and pest had

shown to be constrain in amaranth us

[production.

Recommendation,

• Weeding had shown to reduce both pest

population and disease incidence.

• Therefore weeding can be recommended

on the Amaranthus production.

Thank you All for listening