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Baseline Condition of Parthenium Weed at the Release sites of Biocontrol

Agent/s in Wollenchiti Area of Boset District, Central Ethiopia

Lisanework Nigatu and Tamado TanaHaramaya University, P.O.Box 138, Dire Dawa,

EthiopiaInternational Workshop on Parthenium Weed

July 14-16, 2014, Addis Ababa, Ethiopia

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Background

• Invasive Alien Plant Species (IAPS) are one of the major threats to the ecological and economical wellbeing of Ethiopia.

• Among the different IAPS, parthenium weed is considered to be one of the worst invasive plants in Australia, Asia and Africa

• In Ethiopia, parthenium was first reported from eastern Ethiopia in the 1970s and then rapidly spread to other parts of the country

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Background……..

• It has caused adverse effects on crops, on human health, on livestock health and their products, on the natural ecosystem and livelihood of people.

• The obnoxious characteristics of parthenium weed can be attributed to its high seed production and effective dissemination ability, its inherent allelopathic effects on other plants, its higher phenotypic plasticity, and its ability to withstand a wide range of environmental conditions.

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Background……..

• In management of parthenium, mechanical and manual methods where the plants are uprooted to prevent regeneration before flowering and when the soil is moist enough to facilitate easy removal is practiced in parts of Africa.

• The use of competitive plants to suppress the growth of parthenium has also been suggested

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Background……..

• Biological control using pathogens such as the rust fungus and insects is suggested to be the most cost-effective, environmentally safe and ecologically viable method available.

• Parthenium is ideal for biological control because it can continuously support biological agents because of its ability to have 4 to 7 generations per season, forms pure stands over a large area, and has many natural enemies at its center of origin

• Australia and India have proved that biological control of parthenium is possible and effective. Similar work has started in South Africa to control parthenium using insects.

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Background……..• In an attempt to control the weed, biological control

agent Zygogramma bicolorata was introduced from south Africa following the standard quarantine procedure and has been evaluated under Ethiopian condition for its adaptability and host specificity at Ambo and Wolenchiti.

• After passing all the necessary steps, permit was obtained from concerning government offices for its release around Wolenchiti in central Ethiopia.

• Thus, it is imperative to know the baseline information on parthenium weed infestation and its effect on the livelihood of the farmers in the release sites to assess the impact of bio-control agent in the future.

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Background……..

Thus, the objectives of the study were:• to assess the current above ground and soil seed

bank species composition of sites invaded with parthenium weed; and

• to assess the current impact of parthenium weed on the livelihood of the farmers in the release sites of the biocontrol agent

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Methodology

• The study area is located around Wollenchiti town, 150 km south east of Addis Ababa, in the central Rift valley in Boset district of East Shoa Zone of Oromiya Regional State, Ethiopia

• The study sites fall within 1500-1600 m altitude, receive mean annual rainfall ranging between 700-900 mm with mean minimum and maximum temperatures of 18oC and 34oC, respectively.

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Methodology ….• Assessment of the Above-ground Plant

Community – The above-ground herbaceous plant community was

sampled from three sites using five 1m x 1m quadrats at each site.

– Within each of these quadrats, the plant species were identified and their density was determined by counting the number of individuals of those species present.

– Moreover, their abundance was estimated by a cover percent, which involved a visual estimate of the proportion of the quadrat occupied by these species.

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Methodology ….

• Assessment of the Below-ground Plant Community – To assess the soil seed bank, from each of the three

sites, five soil samples to a depth of 10 cm were collected at random from two opposite corners within each quadrat and mixed together to form a sample.

– The soil samples were taken to the glasshouse and were spread thinly over a sterilized soil mixture in plastic pot

– Two control pots, consisting of just the sterilized soil mixture, were placed among the experimental pots to monitor for any seedlings that may have arisen from this mixture contaminated them from the glasshouse environment.

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Methodology ….

• Assessment of the Below-ground Plant Community – The soil within the pots was watered to maintain its

moisture level close to field capacity. – Pots were assessed weekly for three months for any

newly emerging seedlings.– Once they emerged, seedlings were identified and

counted and then removed and discarded. In the case where immediate identification was not possible, representative individuals were planted into small pots and grown to maturity, to allow for later taxonomic identification. The counted species were expressed in per m2 basis.

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Methodology ….

• Assessment of Socio-economic Impact of Parthenium weed– The study was conducted at three release sites, i.e.

Borcheta, Tedecha and Tribret around Wollenchiti town – At each site representative farmers were selected and

interviewed using structured questionnaire. – Major data collected include awareness about

parthenium, means of its introduction, status of its infestation, its effects on crops, native species, human and animal health and produce and control method used.

– The responses of the framers were summarized using percentages

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RESULTS

• The Above-ground Species Abundance – The highest cover percentage (68.8%), density

(465 plants m-2) and plant height (30.4 cm) of parthenium weed at Borcheta site followed by Tedecha site. On the other hand, plots at Boset Secondary School had the lowest parthenium weed cover percentage, density and height.

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Sites % cover of

parthenium

% cover of

other

species

Density of

partheniu

m per m2

Height of

partheniu

m (cm)

Number of

other

species

Borcheta 68.8 21.2 465 30.4 5.2

Tedecha 55.4 40.5 330 25.3 5.6

Boset

Secondary

School

15 72.8 14 11 5

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RESULTS….

• The Soil Seed bank Composition and Size– From the soil seed bank study, a total of 24 species belonging to

14 plant families were recorded. The most frequent families based on the number of species were Poaceae (7) and Asteraceae (4).

– Annuals were more common (20 taxa) than perennials (4 taxa)– The highest density of parthenium (2065.6 plants m-2) was

recorded in the soil seed bank at Borcheta– Unlike on the aboveground vegetation, the density of

parthenium in the soil seed bank was high at Boset Secondary School indicating the high persistence of parthenium weed seeds in the soil.

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Species Family Species Family

Achyranthes aspera Amaranthaceae Lactuca sativa Asteraceae

Amaranthus dubius Amaranthaceae Leucas martinicesis Lamiaceae

Anagallis arvensis Primulaceae Nicandra physalodes Solanaceae

Anethum foeniculum Apiaceae Parthenium hysterophorus Asteraceae

Argemone ochroleuca Papaveraceae Plantago lancolata Plantaginaceae

Brassica carinata Brassicaceae Setaria pumila Poaceae

Cenchrus ciliaris Poaceae Setaria verticillata Poaceae

Cyperus rotundus Cyperaceae Sonchus oleraceus Asteraceae

Digitaria abyssinica Poaceae Sorghum verticilliforum Poaceae

Eragrostis papposa Poaceae Tribulus terrestris Zygophyllaceae

Eriochloa nubica Poaceae Verbesina encelioides Asteraceae

Euphorbia hirta Euphorbiaceae Vicia sativa Fabaceae

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Density (plants m-2)

Borchetta Boset School Tedecha0

500

1000

1500

2000

2500

Grasses

Other species

Parthenium weed

Sites

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Time

categories

Sites

Borcheta Tedecha Trebiret

Before1986 10 10 60

1987-1991 30 40 30

1992-1997 40 40 10

1998-2003 20 10 -

Awareness about parthenium weed in the study area

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Borcheta Tadecha Trebriet0

10

20

30

40

50

60

70

80

90

Survey sites

High

Medium

Percent of farmers reported the abundance ofpartehnium weed in crop fields

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Sites Cover (%) of

parthenium weed

Reduction in carrying

capacity (%)

Borcheta 68.0 87.9

Tedecha 77.3 86.9

Trebiret 70.9 83.4

Cover percent of parthenium weed and reduction in carrying capacity of grazing land

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Effect of parthenium Sites

Borcheta Tedecha Trebiret)

Bitter test and green color of milk 10 20 50

Changed color of meat and milk 60 30 50

Weight loss, changed color of meat and

milk, breast disease

10 - -

Weight loss, changed color of meat and

milk

- 50 -

Weight loss and breast disease 10 - -

Effect of parthenium weed on animals and their products

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Sites Methods of control used Frequency of weed

control

Herbicides +

hand

weeding

Herbicides +

hand

weeding +

burning

Once Two

times

Three

times

Borcheta 100 - 10 70 20

Tedecha 50 50 10 70 20

Trebiret 40 60 - 90 10

Methods and frequency of parthenium weed control

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Conclusion

• Parthenium weed has enormous seed bank and above ground cover percent in the study area

• Its infestation of has significantly reduced the amount and composition of both the above ground and the seed bank of herbaceous vegetation and negatively affected the livelihood of farmers in the study area.

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Conclusion…..

• Farmers are aware of parthenium, its distribution and means of dissemination, and its negative impact on their wellbeing, crop and livestock production.

• They are also making some efforts to limit the spread of parthenium. However, the success in controlling the spread of parthenium is limited because of the abundance of parthenium seed in the seed bank, its ability to grow fast, weeding after seed setting, not uprooting or uprooting was not done at the appropriate time, and lack of coordinated effort.

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Conclusion…..

• No mich effort is made to control the weed in non-cultivated lands such as grazing areas, wastelands, roadsides, etc except some campaigns which are not done in coordinated and continuous manner.

• Thus, integrated management programs must be carried out to control parthenium weed. Biological control of parthenium can be an ideal option especially in uncultivated lands

• In general, coordinated and concerted efforts must be made by the local people, extension staff, researchers, governments and non-government organizations to mange parthenium weed.

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ACKNOWLEDGMENTS

• USAID through IPM/CRSP for financial support• Haramaya University for providing vehicle and

facilities• Students Tujare Shore and Medhanit Bekele

for field work

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