Hassanein, E.E; Abd El-Hamid, M.M. and M.S., Mekky

1. Assessment of allelopathic potential in Artemisia annua on maize, wheat and their some associated weed species Artemisia annua Artemisia plant By Hassanein, E.E; Abd El-Hamid, M.M. and M.S., Mekky Weed Res., Lab., Field Crop Res. Inst., ARC, Giza Egypt.

2. Objectives : To study the allelopathic effect of wormwood extracts on germination, growth of maize and wheat as well as associated weed species.

3. Materials and Methods A - Laboratory experiments: Two experiments were conducted as follow:-. Experiment I (preliminary experiment): Included 14 concentrations (0, 3, 6, 9, 12, 15, 30, 45, 60, 75, 90, 120, 135 and 140 mg dry weight ml-1c water), replicated twice to determine sensitivity range of maize to the studied extracts. Experiment II: Included 8 concentrations (0, 3, 6, 9, 12, 15, 18 and 21 mg dry weight /ml) replicated three times to determine the required concentration to cause 50% inhibition of seed germination (I50).

4. B - Wire house experiments: - Three pot experiments were conducted to study the effect of wormwood extracts on maize, wheat and associated weed species in pots. Maize experiments: Two pot experiments were conducted to study the effect of wormwood extracts on maize and some weed species in pots as follow:

5. The 1St experiment includedSeven treatments on pots in three replicates as follow: 1-Wormwood extract at 3 g/pot applied at 3 days after sowing (DAS). 2-Wormwood extract at 1.5 g /pot applied at 3 DAS. 3-Wormwood extract at 0.75 g/pot applied at 3 DAS.4-Wormwood extract at 3 g/pot applied at 21 DAS. 5-Wormwood extract at 1.5 g/pot applied at 21 DAS. 6-Wormwood extract at 0.75 g/pot applied at 21 DAS 7- Check (control).

6. The 2nd experiment on maize included seven treatments in pots in replicated three times as follow: 1- Wormwood extract at 1.5 g/pot applied at 3 DAS. 2- Wormwood extract at 0.75 g/pot applied at 3 DAS. 3- Wormwood extract at 0.38 g/pot applied at 3 DAS. 4- Wormwood extract at 1.5 g/pot applied at 21 DAS. 5- Wormwood extract at 0.75 g/pot applied at 21 DAS. 6- Wormwood extract at 0.38 g/pot applied at 21 DAS. 7- Check (control).

7. Wheat experiment: Included five treatments in pots as follow: 1-Wormwood extract by natural white vinegar 2.5% acetic acid at 3 g/pot applied at 2-5 leaves of weed. 2-Wormwood extract by water at 3 g/pot applied at 2-5 leaves of weed. 3-Wormwood extract by water at 3 g plus 3.3 ml acetic 2.5%/pot applied at 2-4 leaves of weed. 4-Natural white vinegar 2.5% acetic acid at 50 ml/pot applied at 2-4 leaves of weed check (control). 5- Check (control).

8. Results and Discussion A- Laboratory experiments: • The required concentration of extract for causing • 50% inhibition of germination of maize was 4 mg/ml.

9. B - Wire house experiments 1 – Maize crop

10. Results of the 1st pot experiment of maize 1- The post emergence application of wormwood extract at the rate of 3 g/pot achieved the highest reduction in number and fresh weight of weeds (100%), however, this dose reduced caused slight phytotoxicity to maize plants. 2-Post emergence application of wormwood extract at the rate of 0.75 g/pot achieved the best reduction of total weeds without any inhibitory effect on maize plant.

11. Table (1): Effect of aqueous acetic 5% extract of wormwood when applied either pre or post emergence on number of weed species under wire house condition (first exp. 4/3/2008).

12. Table (2): Effect of aqueous acetic 5% extract of wormwood when applied either pre or post emergence on number and fresh weight of maize and weed species under wire house condition (first exp. 4/3/2008).

13. Table (3): Effect of aqueous acetic 5% extract of wormwood when applied either pre or post emergence on maize under wire house condition (first exp. 4/3/2008).

14. Artemisia plant

15. Artemisia plant 3 g/pot post-emergence pre-emergence

16. Artemisia plant 1.5 g/pot post-emergence pre-emergence

17. Results of the second pot experiment of maize 1- All studied concentrations of wormwood extract when applied at 3 days after sowing or at 1.5 and 0.75 g/pot when applied at 21 after sowing significantly reduced number and fresh weight of redroot pigweed, purslane and deccan grass. 2- Redroot pigweed and purslane as broad leaved weeds were more susceptible than deccan grass for wormwood extract. 3- Number and fresh weight of maize plant was not significantly affected by all wormwood extract concentration under study.

18. Table (4): Effect of aqueous acetic 5% extract of wormwood when applied either pre or post emergence on number under wire house condition (second exp. 15/4/2008).

19. Table (5): Effect of aqueous acetic 5% extract of wormwood when applied either pre or post emergence on fresh weight of weed species under wire house condition (second exp. 15/4/2008).

20. Table (6): Effect of aqueous acetic 5% extract of wormwood when applied either pre or post emergence on number and fresh weight of maize under wire house condition (second exp. 15/4/2008).

21. 0.75 g/pot pre-emergence post-emergence

22. B - Wire house experiments 2 – Wheat crop

23. Results of the third experiment of wheat 1- Application of wormwood extract by natural white vinegar at 3 g/pot from achieved the best reduction in number and fresh weight of canary grass when applied at 2-4 leaves. 2- Broad leaved weeds were more sensitive than grassy weeds.

24. 3 - Number and fresh weight of most of broad leaved weeds as well as total annual weeds were significantly reduced by aqueous and natural white vinegar of wormwood extract at 3 g/pot when applied at 2-4 leaves. 4-Wheat plants did not affected by different wormwood extracts and natural white vinegar 2.5% acetic acid (control) or water check.

25. Table (5) Effect of aqueous of wormwood and wormwood extracts by natural white vinegar 2.5% acetic acid extracts of wormwood as post emergence on number of weed species.

26. Table (5) Effect of aqueous of wormwood and wormwood extracts by natural white vinegar 2.5% acetic acid extracts of wormwood as post emergence on fresh weight of weed species.

27. Control Natural white vinegar

28. Extract of wormwood in solved natural white vinegar Aqueous wormwood mixed 3.3 ml natural white vinegar

29. Thank you for kind attention