HOST-RANGE STUDY ON THE STEM-BORING WEEVIL (LISTRONOTUS SETOSIPENNIS (COLEOPTERA: CURCULIONIDAE) FOR THE CONTROL OF PARTHENIUM HYSTEROPHORUS IN ETHIOPIA

By Sintu Alemayhu

OBJECTIVE

To evaluate the safety of the stem-boring

weevil, Listronotus setosipennis non-target plant species

DESCRIPTION AND LIFE CYCLE

stem boring weevil Listronotus setosipennis

(Hustache) [Coleoptera: Curculionidae] originally

from Argentina, were introduced from Agricultural

Research Council-Plant Protection Research

Institute (ARC-PPRI) of South Africa in December

2009, to be used for studies in Ethiopia

Nocturnal adults feed on leaves and flowers

Lay eggs in flower heads or leaf bases

hatch 3-5 days later

pupate in soil inside fibrous capsules

Listronotus setosipennis (Coleoptera: Curculionidae

Complete life cycle of Listronotus takes 30-35 days.

DAMAGE

o Adult feeding damage is negligible.o Larval feeding has the ability to kill or prevent

further development of parthenium seedlings. In glasshouse conditions, infestation by

Listronotus weevil at high densities significantly reduced the plant biomass by 21.9% and flower production by 75%.

HOST SPECIFICITY

o Host specificity testing is a critically important step

in the process of introducing natural enemies for

classical weed biological control.

o It provides information upon which the suitability of

a proposed biological control agent can be

assessed (Marohasy1998).

CONT…

Evaluation of the host range of any bioagent comprises of

no-choice tests (test plant species only), followed by

choice tests (test plant with Parthenium) if feeding,

oviposition or development is observed under no-choice

testing on non-target species

The safety of Listronotus setosipennis (Hustache) to non-

target plants was tested under quarantine on

economically important members of the Asteraceae family

and indigenous weed species through no-choice tests

SELECTION OF NON-TARGET SPECIES

The selection of non-target species for host preference testing

was made by a taxonomist from Addis Ababa University.

The centrifugal phylogenetic method was followed in selecting

test plants for testing candidate control agents

The test plant species were identified based on how closely

related they are to Parthenium, whether they are strictly

endemic, near endemic, cultivated, or indigenous to Ethiopia.

Figure 1. Diagrammatic representation of the tribe Heliantheae and some crop plants (adapted by Lorraine Strathie from Wapshere, A. J. 1974).

MATERIALS AND METHODS

Area description The experiment was conducted under quarantine

condition at Ambo Plant Protection Research

Center (APPRC) 109km West of Addis Ababa.

The average temperature is ranges from 10o to

30o C and relative humidity at 50-87 % in the

quarantine facility

CULTURING OF L. SETOSIPENNIS

Adult feeding and oviposition were tested using nylon mesh test cages with metal frames(0.5m x 0.5m x 1m), with two holes for potted plants.

All corners and joints were sealed with silicone to prevent escape of weevils through gaps.

The safety of Listronotus setosipennis (Hustache) to 39 non-target plants consisting of nineteen major crop species mostly used as

food and export Twenty crops and other plant species, belonging

to the family Asteraceae which includes two species of Helianthus annus , six species Guizotia abyssinica, both of which are important oil crops in the country . and four species of Bidens

CONT…

o No-choice tests were designed to test whether the bio-agent

feeds, lay eggs and survive on a test plant when it has no

access to target weed Parthenium.

o All the test plants were grown or transplanted into plastic

pots(22cm X 18 cm), containing the mixture of sand 25%,

compost/humus 25% and 50% soil

o grown up to the required test stage by providing every

agronomic management under lath-house

CONT…

o Healthy and similar size Plant with flowers, were

selected and placed in a cage after being washed

o Five mating pairs of adult L. setosipennis, obtained

from same age group of adults that had been kept for

2-3 weeks, were released into each cage.

o Sodium hypochlorite solution (2%) was sprayed on

the leaves and soil to prevent any disease occurrence.

o The experiment was replicated three times in CRD

and one plant per cage was used.

CONT…

After 7 days of exposure all adults were removed

from each test plant and the number of adults that

survived, died and missed was recorded

All plant parts, including leaf axils, stems and

petioles, were carefully examined for ovipostion and

feeding. Eggs were counted after dissecting flowers

and examining plants under a microscope.

• The blue arrow shows frass • The read arrow shows egg

Tagetes minuta Helianthus annus (oissa) Bidens pachyloma

G.abysinica (kuyyu)

Vernonia galamensis

No Scientific Name Common name / variety

Total no of egg

Total mean S.D S.E

Parthenium hystrerophorous (control)

partehnium 8648 38.96 50.01 3.37

1. Eragrostis tef Teff 0 0 0.00 0.002. Eragrostis tef Teff v DZ-c37 0 0 0.00 0.003. Sorghum bicolor Sorghum 0 0 0.00 0.004. Zea mays Maize 0 0 0.00 0.005. Hordeum vulgare Barley 0 0 0.00 0.006. Triticum aestivum Wheat 0 0 0.00 0.007. Cicer arietinum Chick pea 0 0 0.00 0.008. Lens cultinaris Lentil 0 0 0.00 0.009. Gossipium sp. Cotton var, Arba 0 0 0.00 0.0010. Sesamum indicum Sesame

0 0 0.00 0.00 var. Abasena11. Sesamum indicum var. Tate 0 0 0.00 0.0012. Sesamum indicum var.5 0 0 0.00 0.0013. Pisum sativum L. Field peas 0 0 0.00 0.0014. Vicia faba Faba beans 0 0 0.00 0.0015. Lathyrus sativus Grass pea, Indian vetch 0 0 0.00 0.0016. Solanum tuberosum Potato local 0 0 0.00 0.0017. Solanum lycopersicum Tomato 0 0 0.00 0.0018. Capsicum sp. Pepper 0 0 0.00 0.0019 Corchorus sp. 0 0 0.00 0.00

Table 1. Result of Host-Specificity of Listronotus setosipennis (Hustache) on major crops

Evaluation of species related to PartheniumNo Scientific/variety name Common name Total no of

egg Total mean S.D S.E

1. Guizotia abyssinica (Local) niger seed 0 0 0.00 0.002. G. abyssinica (Fogera) niger seed 0 0 0.00 0.003. G. abyssinica (ESTE) niger seed 0 0 0.00 0.004. G. abyssinica (Kuyu) niger seed 0 0 0.00 0.005. G. abyssinica (Shambu) niger seed 0 0 0.00 0.006. G. abyssinica (Ghinchi) niger seed 0 0 0.00 0.007. Helianthus annuus (oissa) sunflower 0 0 0.00 0.00

8. Helianthus annuus (R.B) sunflower 0 0 0.00 0.00

9. Carthamus tinctorius Safflower 0 0 0.00 0.0010. Vernonia galamensis Iron Weed 0 0 0.00 0.0011. Lactuca sativa Lettuce 0 0 0.00 0.0012. Bidens pilosa Black jack 0 0 0.00 0.00

13 Bidens Pachyloma Adeyabeba (Amharic) 0 0 0.00 0.00

14 Bidens ghedoensis 0 0 0.00 0.0015 Bidens sp 0 0 0.00 0.0016 Guizotia scabra Metch (Amharic) 0 0 0.00 0.0017. Conyza bonariensis Horseweed, Asthmaweed 0 0 0.00 0.00

18. Galinsoga parviflora Gallant soldier 0 0 0.00 0.0019. Tagetes minuta Black mint 0 0 0.00 0.0020. Flaveria trinervia Clustered yellow tops 0 0 0.00 0.0021. Parthenium hysterophorus parthenium 8648 38.96 50.01 3.37

CONCLUSION

The concern that the agent, Listronotus setosipennis, might attack non- target crops and plants was resolved through a quarantine test against crops and plants that are closely related to Parthenium and others that are economically important and indigenous to Ethiopia.

Therefore there was no need to go for choice test since no oviposition took place in no choice test

Thank You