Chemical control of Ailanthus Altissima by using different techniques

Contact CHEMICAL CONTROL OF AILANTHUS ALTISSIMA BY USING DIFFERENT TECHNIQUES Ailanthus altissima is considered an invasive weed in natural ecosystems in Europe (Europe, R 2019/1262). Its invasion alters the ecosystem functioning, modifying native plant communities and wildlife habitat and threatening biodiversity. The Conservation Park of Serra de Collserola in Barcelona (Catalonia, Spain) has an area of 8,300 ha of which 40 ha have been invaded by A. altissima. Glyphosate is one of the most effective herbicide for this species, but because of a ban for its use in many cities in Barcelona region, other active ingredients should must be tested. The use of herbicides is known as an effective method (Burch and Zedaker 2003). Evaluation of effectivity of different active ingredient by using different three t echniques, stem injection, cut stump and basal bark in autumn. Jordi Soler1, Jordi Izquierdo1, Joan Vilamú2 [email protected] Cut stump was the only method that controlled all trees at the first count (6 month after treatment, MAT). Stem injection was the only technique that achieved total effectivity at the third count (11 MAT), and fluroxypyr was the slowest herbicide. Complete mortality for basal bark technique was observed at third count, except fluroxypyr that did not control all trees. Control trees did not show enough effectivity as expected (Figures 4, 5 and 6). As in our cut stump injection results, other authors found that the combination of cutting trees plus herbicide gave better results than only herbicide application. Another important point, is that results should be evaluated for more than one year, to prevent undesirable results by resprouts (Kowarik & SaumeI, 2007). Monitoring for few years showed that resprouts can appear (Fogliatto et al., 2020). Other studies found that basal bark applications with fluroxipyr gave better results than Triclopyr in Triadica sebifera trees (Enloe et al., 2015). 1 Departament d'Enginyeria Agroalimentària i Biotecnologia, UPC. Campus Baix Llobregat. Ed. D4. 08860 Castelldefels 2Servei de Medi Natural. Parc Natural de la Serra de Collserola. Ctra. de l'Església, 92, 08017 Barcelona Table 1. Characteristics of applications, * active ingredient injected per tree. Triclopyr + aminopiralid and Clopiralyd + triclopyr are effective for diameters less than 10 cm for our three techniques. The addition of a surfactant or oil for basal bark treatments, could improve the effectivity (Burch and Zedaker, 2003). As many prohibitions of active ingredients occurs in Europe, fluroxypyr could be an alternative to glyphosate or commercial mixtures that contain triclopir. This work is part of a PhD, and final results will contain evaluation along three years. Three different herbicides were applied diluted in water (Triclopyr + aminopyralid, Fluroxypyr and Clopyralid + triclopyr) during October 2021. Every product was applied to a group of 10 trees with 3 replications plus a control in trees with diameters less than 10 cm. In stem injection, four holes were done with a drill using an 8mm drill bit on the basal part of the uncut trunks, applying the herbicides with a syringe into the holes. Four holes were also done for cut stump application, in which trees were cut above the holes, applying the herbicides with a syringe into the holes. For basal bark, herbicides were applied using a brush, painting the first 100 cm of the stem. The same amount of broth was applied for each technique. For control trees only water was applied (Figures 1, 2 and 3). Survival of the trees was monitored three times (April, June and September 2022), monitoring the affectation of the trees (dead or alive). (Table 1). Results and discusion Conclusions Introduction Objectives Materials and methods Date of application Treatments Techniques Dose (%) *ai (ml) October 2021 Triclopyr 24% + aminopyralid 3% (Tordon Star, Corteva) Stem injection Cut stump Basal bark 60 1,2 + 0,2 Fluroxypyr 20% (Starane 20, Corteva) 75 1,4 Clopyralid 6% + triclopyr 24% (Silvanet, Corteva) 80 0,5 + 2,1 Control: water 100 Fig 1. Stem injection detail. Fig 2. Cut stump injection detail. Fig 3. Basal bark detail. Stems have been painted below the blue mark. Fig. 5. Mortality of trees treated by cut sump injection during October 2021 (diameter < 10cm). All treatments except control trees, had identical results. Fig. 6. Mortality of trees treated by basal bark during October 2021 (diameter < 10cm). Fig. 4. Mortality of trees treated by stem injection during October 2021 (diameter < 10cm). Triclopyr + aminopyralid and Clopyralid + Triclopyr had identical results. 0 10 20 30 40 50 60 70 80 90 100 24/04/2022 18/06/2022 16/09/2022 Mortality (%) Basal bark (brush) Triclopyr (24%) + aminopyralid (3%) 60% Fluroxypyr (20%) 75% Clopyralid (6%) + triclopyr (24%) 80% Control 0 10 20 30 40 50 60 70 80 90 100 24/04/2022 18/06/2022 16/09/2022 Mortality (%) Cut stump injection Triclopyr (24%) + aminopyralid (3%) 60% Fluroxypyr (20%) 75% Clopyralid (6%) + triclopyr (24%) 80% Control 0 10 20 30 40 50 60 70 80 90 100 24/04/2022 18/06/2022 16/09/2022 Mortality (%) Stem injection Triclopyr (24%) + aminopyralid (3%) 60% Fluroxypyr (20%) 75% Clopyralid (6%) + triclopyr (24%) 80% Control