Acta agriculturae Slovenica, 121/2, 1–8, Ljubljana 2025 doi:10.14720/aas.2025.121.2.16247 Original research article / izvirni znanstveni članek Efficacy and phytotoxicity of post emergence herbicides in garlic Dionatan SULIANI 1, Wendel Paulo SILVESTRE 2,3*, Taísa DAL MAGRO 4 Received September 26, 2023; accepted March 25, 2025 Delo je prispelo 26. septmeber 2023, sprejeto 25. marec 2025 1 University of Caxias do Sul, Course of Agronomy; Caxias do Sul, Brazil. dsuliani@ucs.br (ORCID: 0009-0004-6844-1299). 2 University of Caxias do Sul, Course of Agronomy and Postgraduate Program in Process Engineering and Technologies; Caxias do Sul, Brazil. wpsilvestre@ucs.br (ORCID: 0000-0002-9376-6405). 3 Corresponding author. E-mail: wpsilvestre@ucs.br 4 Empresa de Pesquisa Agropecuária e Extensão Rural de Santa Catarina (EPAGRI); Ituporanga, Brazil. taisamagro@epagri.sc.gov.br (ORCID: 0000-0001-9028-5174). Efficacy and phytotoxicity of post emergence herbicides in garlic Abstract: The incidence of weeds in the garlic crop inter- feres with the quality and quantity of the harvest. This study aimed to evaluate the efficiency of herbicides in different com- binations of sequential applications during the cultivation of garlic. The experiment was carried out in a randomized block design, with ten treatments and four replications. The treat- ments consisted of sequential applications of the herbicides pendimethalin, pyroxasulfone/flumioxazin, ioxynil, and pen- dimethalin. The doses of Herbadox® (pendimethalin) were 4.0 l∙ha-1, Totril® (ioxynil) 1.5 l∙ha-1, and Kyojin® (pyroxasulfone/ flumioxazin) 0.15 l∙ha-1. Treatments consisted of sequential ap- plications of herbicide combinations. Applications were per- formed 7, 58, 97, and 128 days after planting. Phytotoxicity on the crop, efficacy in weed control, bulb classification, and pro- ductivity were evaluated. The results were submitted to ANO- VA, and the means were compared by the Scott-Knott test. The sequential application of pyroxasulfone/flumioxazin at 7 days after planting (DAP), ioxynil at 58 DAP, pendimethalin at 97 DAP, and pyroxasulfone/flumioxazin at 128 DAP (T7) stood out (96–100 % control of weeds, average productivity of 11.42 t·ha-1), which presented the best results relative to phytotoxicity, weed control, bulb classification, and crop productivity. Key words: phytotoxicity, efficacy, weed control, post- emergence. Učinkovitost in fitotoksičnost herbicidov uporabljenih po vzniku česna Izvleček: Pojavnost plevelov v nasadih česna vpliva na količino in kakovost pridelka. V raziskavi je bila ovrednotena učinkovitost herbicidov v različnih kombinacijah v zapored- nih nanosih med gojenjem česna. Poskus je bil zasnovan v naključni bločni obliki, z desetimi obravnavanji in štirimi po- novitvami. Obravnavanja so obsegala zaporedno uporabo her- bicidov kot so pendimetalin, piroksasulfon/flumioksazin, iok- sinilin pendimetalin. Odmerki Herbadox-a® (pendimetalin) so bili 4,0 l∙ha-1, Totril-a® (ioksinil) 1,5 l∙ha-1in Kyojin-a® (piroksa- sulfon/flumioksazin) 0,15 l∙ha-1. Obravnavanja so bila izvedena v zaporednih kombinacijah herbicidov. in sicer 7, 58, 97 in 128 dni po sadnji. Ovrednotene so bile fitotoksičnost za pos- evek, učinkovitost zatiranja plevelov, klasifiklacija čebulic in produktivnost. Rezultati so bili obdelani z ANOVA, poprečja so bila primerjana s Scott-Knottovim testom. Zaporedna up- oraba piroksasulfona/flumioksazina 7 dni po sadnji (DAP), ioksinila 58 DAP, pendimetalina 97 DAP in piroksasulfona/ flumioksazina 128 DAP (T7) je izstopala (96–100 % nadzor plevelov, poprečna produktivnost 11,42 t·ha-1), kar je predstavl- jalo najboljše rezultate glede na fitotoksičnost, nadzor plevelov, klasifikacijo čebulic in produktivnost česna. Ključne besede: fitotoksičnost, učinkovitost nadzora ple- velov po vzniku 2 D. SULIMANI et al. Acta agriculturae Slovenica, 121/2 – 2025 1 INTRODUCTION Garlic cultivation in Brazil is a profitable source for both small-family farmers and large producers. This crop is very important in generating jobs (Meneguzzo et al., 2022). In 2021, 167,102 t of this crop were harvested, with an average yield of 12.8 t∙ha-1, mostly in small farms (about 1–2 ha), totaling an acreage of 13,544 ha (IBGE, 2023). The garlic crop presents a reduction in develop- ment when there is the simultaneous presence of weeds due to its slow initial growth, with low height and narrow and erect leaves that do not cover the soil surface. The critical period of garlic competition with weeds occurs between the first 20 days after emergence and during bulb maturation. Despite not interfering so much with maturation, weeds make manual harvesting difficult and mechanical harvesting unfeasible (Patil et al., 2016; Sid- dhu et al., 2018). The primary weeds in colder periods in southern Brazil are the lesser swinecress (Coronopus didymus (L.) Sm.), wild radish (Raphanus spp.), chickweed (Stellaria media (L.) Vill.), broad-leaved dock (Rumex obtusifolius L.), and Italian ryegrass (Lolium multiflorum Lam.) (Uzo & Currah, 1990). In warmer periods, crabgrass (Digi- taria spp.), alexandergrass (Urochloa plantaginea (Link) R.D.Webster), barnyardgrass (Echinochloa spp.), beggar- tick (Bidens pilosa L.), wild poinsettia (Euphorbia hetero- phylla L.), arrowleaf sida (Sida spp.), starbur (Acantho- spermum spp.), potato weed (Galinsoga parviflora Cav.), and pigweed redroot (Amaranthus spp.) occur (Abouzi- ena & Haggag, 2016). Weeds that grow in summer and spring seasons do not tolerate frost (Guerra et al., 2020). Pre-emergence herbicides are widely used in pre- planting and, in some cases, incorporated into the soil. Post-emergence herbicides control weeds that are in full physiological development. At post-emergence, the management of weeds becomes problematic as they grow (Das & Mondal, 2014; Wilkinson et al., 2015). Pre-emergence herbicides, such as pendimethalin (Herbadox®), which inhibits cell division, and linuron (Afalon®), a photosystem II inhibitor, are widely used by garlic producers in Brazil. These active principles have a good residual in the soil, keeping the area clean of weeds. Also, there is a large offer of these products on the market (Guerra et al., 2020). Kyojin® is a selective, contact, and systemic herbi- cide composed of pyroxasulfone, a cell division inhibitor, and flumioxazin, a Protox inhibitor. It is broad-spectrum effective against many weeds of the garlic cultivation (Agrofit, 2022). Flumioxazin successfully controlled weeds in garlic crops (Guerra et al., 2020). This work aimed to evaluate the efficiency of differ- ent herbicide combinations in the garlic crop, applied se- quentially, with varying application intervals. 2 MATERIALS AND METHODS The experiment was conducted on a farm in the municipality of São Marcos, Rio Grande do Sul State (geographical coordinates: 28°54’ S, 51°07’ W, and an al- titude of 679 m above sea level). The local climate is clas- sified as Cfa (subtropical humid climate with mild sum- mer), characterized by an average yearly rainfall of 1,688 mm, an average minimum temperature of 13 °C, and an average maximum temperature of 23 °C (Alvares et al., 2013). During the experiment, the average temperature was 17.3 °C, varying between 0.6 °C and 33.4 °C, and the accumulated rainfall in the period was 571.8 mm (IN- MET, 2023). The experimental design used was randomized blocks with four replications. The plots consisted of six rows spaced 0.2 m apart, 5 m long, and 1.2 m wide, to- taling an area of 6 m2. The two central lines of each plot were considered useful for evaluation and harvesting, the remainder being considered borders. The garlic cultivar ‘San Valentin’ was planted in the experiment. The bulbs underwent viral cleaning and were in their third generation, coming from the 2020/2021 harvest. The bulbs were selected and classified, subse- quently submitted to vernalization, where they remained for 48 days in a cold chamber at a temperature of 2 ºC. The area was prepared with a duck foot plow, har- rowing and filling. A marker roller coupled to a rotary hoe was used for planting the bulbil, helping with the planting work. The fertilization was carried out before planting with 60 kg∙ha-1 of N, 375 kg∙ha-1 of P, and 180 kg∙ha-1 of K (750 kg of NPK fertilizer Topmix® 4-25-12, with 4 wt.% of nitrogen compounds, 25 wt.% of phospho- rus compounds and 12 wt.% of potassium compounds) before planting and two topdressing applications with a total of 36 kg·ha-1 of N and 96 kg·ha-1 of K (100 kg per hectare with NPK 9-00-24, containing 9 wt.% of nitrogen compounds and 24 wt.% of potassium compounds) dur- ing crop development. The bulbils underwent phytosanitary treatments, in which the fungicides captan and abamectin were used at doses of 2.0 ml∙l-1 and 2.5 ml∙l-1, respectively, before ver- nalization. Planting was carried out on July 20, 2022, and microsprinklers provided irrigation at the beginning of the crop cycle. The tested treatments, active ingredients, and doses are compiled in Table 1. Herbicide application started seven days after plant- ing (DAP) of the crop, in pre-emergence of weeds; the second application occurred at 58 DAP; the third ap- 3 Efficacy and phytotoxicity of post emergence herbicides in garlic Acta agriculturae Slovenica, 121/2 – 2025 plication occurred at 97 DAP, and the last application was performed at 128 DAP. The herbicides were always applied in the morning. The equipment used to apply the treatment was a knapsack sprayer pressurized with CO2, calibrated with a constant pressure of approx. 2.5 kPa, which provided a spray volume of 500 l∙ha-1. Other aspects of cultural management, such as phytosanitary treatments and sprinkler irrigation, were carried out dur- Treatment DAP* Active ingredient Dose (g·ha-1) Dose (l·ha-1) Treatment 1 (Infested control) - - - - Treatment 2 (Weeded control) - - - - Treatment 3 7 Pendimethalin¹ 1,600 4.0 58 Pyroxasulfone/flumioxazin ² 45/30 0.15 97 Ioxynil³ 375 1.5 128 Pendimethalin 1,600 4.0 Treatment 4 7 Pyroxasulfone/flumioxazin 45/30 0.15 58 Pendimethalin 1,600 4.0 97 Ioxynil 375 1.5 128 Pyroxasulfone/flumioxazin 45/30 0.15 Treatment 5 7 Ioxynil 375 1.5 58 pendimethalin 1,600 4.0 97 Pyroxasulfone/flumioxazin 45/30 0.150 128 Ioxynil 375 1.5 Treatment 6 7 pendimethalin 1,600 4.0 58 Ioxynil 375 1.5 97 Pyroxasulfone/flumioxazin 45/30 0.15 128 pendimethalin 1,600 4.0 Treatment 7 7 Pyroxasulfone/flumioxazin 45/30 0.15 58 Ioxynil 375 1.5 97 pendimethalin 1,600 4.0 128 Pyroxasulfone/flumioxazin 45/30 0.15 Treatment 8 7 Ioxynil 375 1.5 58 Pyroxasulfone/flumioxazin 45/30 0.15 97 pendimethalin 1,600 4.0 128 Ioxynil 375 1.5 Treatment 9 7 Pyroxasulfone/flumioxazin 45/30 0.15 58 Pyroxasulfone/flumioxazin 45/30 0.15 97 Ioxynil 375 1.5 128 Pyroxasulfone/flumioxazin 45/30 0.15 Treatment 10 7 Ioxynil 375 1.5 58 Pyroxasulfone/flumioxazin 45/30 0.15 97 Pyroxasulfone/flumioxazin 45/30 0.15 128 Ioxynil 375 1.5 Table 1: Compilation of treatments applied and their composition, days after planting, active ingredient, and doses of commercial product. São Marcos, UCS, 2022. * – Days after planting. ¹ – Herbadox®; ² – Kyojin®; ³ – Totril®. Source: Authors (2025) 4 D. SULIMANI et al. Acta agriculturae Slovenica, 121/2 – 2025 ing the crop cycle when necessary, according to farmer’s expertise. The evaluation of weed control was carried out at the end of the cycle, in the pre-harvest period. The assess- ment of the classification of the bulbs occurred at the end of the crop cycle, quantifying, and classifying the bulbs of the two central lines. The bulbs were measured using an analog caliper and classified according to Mercosul GMC resolution 05/21 (Mercosul, 2021), considering the largest cross-sectional diameter of the bulb, expressed in millimeters (mm). Thus, bulbs > 56 mm were classified as number 7, > 47–56 mm as number 6, > 42–47 mm as number 5, > 37–42 mm as number 4, and > 32–37 mm as number 3 (Brazil, 1992). Bulbs smaller than 32 mm do not fit the regulation. Therefore, they were classified as industrial garlic. The productivity evaluations were performed with a digital electronic scale (ALC500, Marte, Brazil), where ten random bulbs were weighed, harvested in each block, and divided by the number of bulbs present in the weigh- ing. Per repetition (block), 1.1 kg were planted. With this, the average productivity was estimated considering 1,000 kg·ha-1 of planted bulbils. Phytotoxicity symptoms were evaluated seven days after each application (DAA). Phytotoxicity scores were based on visual criteria, based on control, considering a scale from zero to 100 %, where zero represents the ab- sence of injuries caused by the herbicides and 100 % (one hundred) corresponded to the death of the plants. For the visual evaluations of the infested plants, percentages of control provided by the herbicides were applied rela- tive to the control (T1 – infested control) (SBCPD, 1995). The results were evaluated for homoscedasticity (Levene’s test) and normality (Shapiro-Wilk’s test), be- ing submitted to the Analysis of Variance (ANOVA). The means of the treatments were compared by the post hoc test of multiple comparison of means of Scott- Knott at a 5 % error probability (α = 0.05). The statistical analyses were performed using the AgroEstat® software (Brazil). 3 RESULTS AND DISCUSSION For the evaluated variables, there was a statistical difference between the herbicide treatments tested (Ta- bles 2 to 6). The results of phytotoxicity to garlic crops caused by each herbicide treatment are presented in Ta- ble 2. The phytotoxicity caused by the different herbicides in the garlic crop was presented as follows: the combi- nations started seven days after planting (DAP) with py- roxasulfone and flumioxazin at a dose of 0.15 l·ha-1 and ioxynil at 1.5 l·ha-1 caused a reduction in development relative to the weeded control (T2). In contrast, pendi- methalin at a 4.0 l·ha-1 dose did not cause crop phyto- toxicity. At 58 DAP, garlic was very susceptible to injuries caused by the herbicides tested after the second applica- tion. Yellowing symptoms were quite noticeable, where all herbicides showed percentages of phytotoxicity higher than 7 DAP. The active ingredient ioxynil (Totril®) caused less phytotoxicity than the other ingredients at a 1.5 l·ha-1 dose. The combination in which the association pyroxa- sulfone/flumioxazin was applied at 97 DAP caused phy- totoxicity symptoms of up to 33 % of the leaf area with signs of yellowing and whitish lesions caused by pyroxas- ulfone and flumioxazin. It is worth mentioning that there was a higher incidence of bacterial diseases in the plots Treatment Phytotoxicity (%) in 7 DAA 7 DAP 58 DAP 97 DAP 128 DAP T1 – Infested Control 0 c 0 f 0 c 0 c T2 – Weeded Control 0 c 0 f 0 c 0 c T3 – Pen¹, Pyr/Flu², Iox³, Pen 0 c 20 c 0 c 10 b T4 – Pyr/Flu, Pen, Iox, Pyr/Flu 7 a 17 d 0 c 16 a T5 – Iox, Pen, Pyr/ Flu, Iox 4 b 17 d 33 a 5 c T6 – Pen, Iox, Pyr/ Flu, Pen 0 c 10 e 20 b 0 c T7 – Pyr/Flu, Iox, Pen, Pyr/Flu 5 b 17 d 0 c 11 b T8 – Iox, Pyr/Flu, Pen, Iox 4 b 36 a 0 c 0 c T9 – Pyr/Flu, Pyr/ Flu, Iox, Pyr/Flu 5 b 28 b 0 c 17 a T10 – Iox, Pyr/Flu, Pyr/Flu, Iox 4 b 30 b 20 b 16 a Coefficient of varia- tion (%) 26.7 11.1 49.3 39.9 Table 2: Results of visual assessment of phytotoxicity symptoms in the garlic crop, seven days after the application (DAA) of her- bicide combinations, at different development crop stages. São Marcos, UCS, 2022. ¹ – pendimethalin; ² – pyroxasulfone/flumioxazin; ³ – ioxynil. The ad- opted doses were 4.0 l·ha-1 for pendimethalin®, 0.15 l·ha-1 for pyroxasul- fone/flumioxazin, and 1.5 l·ha-1 for ioxynil. DAA – days after applica- tion of treatments; DAP – days after crop planting. Means in column followed by the same letter do not differ statistically by the Scott-Knott test at a 5 % error probability. Source: Authors (2025). Acta agriculturae Slovenica, 121/2 – 2025 5 Efficacy and phytotoxicity of post emergence herbicides in garlic where pyroxasulfone/flumioxazin was applied at 0.15 l·ha-1 compared to the weeded control (T2), consequent- ly, due to the lesions caused by the herbicide. Pyroxasulfone and flumioxazin, when applied at 128 DAP, caused greater phytotoxicity than the other herbicides tested. However, the damage caused was lower than that seen at 97 DAP, not leading to the death of the culture of interest at the dose used. On the other hand, the ioxynil and pendimethalin principles caused a lower degree of injuries caused by phytotoxicity in the crop when applied at 128 DAP. The damage capacity of the pyroxasulfone/flu- mioxazin association at a dose of 0.15 l·ha-1 was noticed on garlic plants at different stages of crop development, where significant damage to the leaves stood out. Among the best combinations, which caused the lowest percent- ages of phytotoxicity, those that started with applying pendimethalin at a dose of 4.0 l·ha-1 stood out. The main weeds occurring in the experimental area were the wild carrot (Daucus carota L.), speedwell (Veronica spp.), potato weed (Galinsoga parviflora) and lesser swinecress (Coronopus didymus). The results of the Treatment Control (%) Potato weed Lesser swinecress Wild carrot Crab- grass T1 – Infested Control 0 b 0 b 0 d 0 c T2 – Weeded Control 100 a 100 a 100 a 100 a T3 – Pen¹, Pyr/Flu², Iox³, Pen 100 a 97 a 58 b 96 b T4 – Pyr/Flu, Pen, Iox, Pyr/Flu 98 a 97 a 68 b 98 a T5 – Iox, Pen, Pyr/ Flu, Iox 85 a 87 a 31 c 93 b T6 – Pen, Iox, Pyr/ Flu, Pen 100 a 100 a 68 b 100 a T7 – Pyr/Flu, Iox, Pen, Pyr/Flu 96 a 97 a 100 a 100 a T8 – Iox, Pyr/Flu, Pen, Iox 98 a 97 a 58 b 100 a T9 – Pyr/Flu, Pyr/ Flu, Iox, Pyr/Flu 96 a 100 a 79 b 100 a T10 – Iox, Pyr/Flu, Pyr/Flu, Iox 96 a 100 a 68 b 100 a Coefficient of varia- tion (%) 9.8 9.6 20.5 2.6 Treatment Classification - Class (%) C7 C6 C5 C4 C3 Industry T1 – Infest- ed Control 0 b 0 d 0 b 5 b 57 a 37 a T2 – Weed- ed Control 0 b 81 a 18 b 0 b 0 c 0 b T3 – Pen¹, Pyr/Flu², Iox³, Pen 2 b 25 b 52 a 20 a 0 c 0 b T4 – Pyr/ Flu, Pen, Iox, Pyr/Flu 0 b 30 b 50 a 17 a 2 c 0 b T5 – Iox, Pen, Pyr/ Flu, Iox 0 b 2 c 47 a 32 a 17 b 0 b T6 – Pen, Iox, Pyr/Flu, Pen 0 b 32 c 47 a 20 a 0 c 0 b T7 – Pyr/ Flu, Iox, Pen, Pyr/Flu 7 a 50 b 32 a 5 b 2 c 0 b T8 – Iox, Pyr/Flu, Pen, Iox 0 b 37 c 45 a 15 a 2 c 0 b T9 – Pyr/ Flu, Pyr/Flu, Iox, Pyr/Flu 0 b 52 b 40 a 5 b 0 c 0 b T10 – Iox, Pyr/Flu, Pyr/Flu, Iox 0 b 10 d 32 a 37 a 12 b 2 b Coefficient of variation (%) 33.8 52.6 43.1 16.4 78.9 84.7 Table 3: Control (%) of potato weed (Galinsoga parviflora), lesser swinecress (Coronopus didymus), wild carrot (Daucus carota), and speedwell (Veronica spp.) in garlic crop due to dif- ferent herbicides applied in the pre-harvest period. São Marcos, UCS, 2022. ¹ – pendimethalin; ² – pyroxasulfone/flumioxazin; ³ – ioxynil. The adopted doses were 4.0 l·ha-1 for pendimethalin®, 0.15  l·ha-1 for py- roxasulfone/flumioxazin, and 1.5 l·ha-1 for ioxynil. DAA – days after application Means in column followed by the same letter do not differ statistically by the Scott-Knott test at a 5 % error probability. Source: Authors (2025). Table 4: Classification of garlic bulbs, following the MAPA reg- ulation 242, treated with different combinations of herbicides during the crop cycle. São Marcos, UCS, 2022. ¹ – pendimethalin; ² – pyroxasulfone/flumioxazin; ³ – ioxynil. The adopted doses were 4.0 l·ha-1 for pendimethalin®, 0.15  l·ha-1 for py- roxasulfone/flumioxazin, and 1.5 l·ha-1 for ioxynil. DAA – days after application Means in column followed by the same letter do not differ statistically by the Scott-Knott test at a 5 % error probability. Source: Authors (2025). Acta agriculturae Slovenica, 121/2 – 20256 D. SULIMANI et al. control percentage of each weed species relative to the treatments tested are compiled in Table 3. For the control of potato weed and lesser swinecress (Table 3), all combinations showed excellent control (> 85 %), with emphasis on the combination that started with pendimethalin at doses of 4.0 l·ha-1 at 7 DAP, ioxynil 1.5 l·ha-1 at 58 DAP, pyroxasulfone/flumioxazin 0.15 l·ha-1 at 97 DAP and pendimethalin again at 128 DAP, showing total control (100 %) of both evaluated weeds. The association pyroxasulfone/flumioxazin, ioxynil, pendimethalin, and pyroxasulfone/flumioxazin (T7) stood out, which promoted total control (100 %) of these invasive species. The combination of ioxynil, pendimethalin, pyroxa- sulfone/flumioxazin, and ioxynil (T5) proved to be the least effective concerning the other treatments, showing 93 % control of crabgrass, but only 31 % of control for wild carrot (Table 3). These differences are due to the specific sensitivity of each species to herbicides, resulting in greater control of crabgrass when compared to wild carrot. Data on bulbs’ classification according to the herbi- cide treatments used are compiled in Table 4. Differences in bulb caliber were significant in class 7 (C7), highlighting the use of pyroxasulfone/flumioxa- zin 0.15 l·ha-1 in the first application, followed by ioxynil 1.5 l·ha-1, pendimethalin 4.0 l·ha-1 and pyroxasulfone/flu- mioxazin in combination. In this treatment, 7 % of the total bulbs were classified as class 7, 50 % as class 6, and 32 % as class 5. Notably, weed control was important for greater uniformity and size of bulbs in the garlic crop. The infested control (T1) showed statistical varia- tion about the other treatments for bulbs smaller than 32 mm, with 37 % of the production as industry garlic, which indicates the negative effect of not controlling the weed species present during the development of the crop. Data referring to the mass of bulbs and estimated productivity of the crop with the different herbicide ap- plication regimes are presented in Table 5. According to Tables 4 and 5, the combination that stood out negatively from the others was ioxynil, pen- dimethalin, pyroxasulfone/flumioxazin, and ioxynil (T5), which had the smallest caliber of bulbs, being inferior to the other treatments due to the low control of weeds. Among the evaluated treatments (Table 5), the com- bination of pyroxasulfone/flumioxazin herbicides at 7 DAP, ioxynil at 58 DAP, pendimethalin at 97 DAP, and pyroxasulfone/flumioxazin in its last application (T7), which had an average mass of 49 g per bulb stood out. The estimated productivity of 11.42 t·ha-1 was very close to the weeded control (T2 – 11.47 t·ha-1). The residual effect of the product pyroxasulfone/flu- mioxazin at 0.15 l·ha-1 was notorious when applied at 7 DAP, presenting an excellent residual effect and control- ling the emergence of weeds, which kept the crop free of competition. The combination that had the slightest effect on yield was the one started with ioxynil, pendi- methalin, pyroxasulfone/flumioxazin, and ioxynil (T5), with an estimated yield of 7.37 t·ha-1, considering 1,000 kg·ha-1 of bulbils planted. Wilkinson et al. (2015) pointed out that the symp- toms of poisoning by photosystem II inhibitors (FSII), such as ioxynil, appear quickly and are characterized by interveinal chlorosis and leaf edge chlorosis in sea- grass. These symptoms develop rapidly after herbicide application, as seen within seven days after application. Therefore, the combination of herbicides that stood out, showing less phytotoxicity at 58 DAP, was pendimetha- lin, ioxynil, pyroxasulfone and flumioxazin, and pen- dimethalin (T6). As highlighted by Siddhu et al. (2018), in addition to favorable climatic conditions, the emergence of diseases is associated with injuries or stress caused by applying chemical pesticides, mainly post-emergence herbicides. Treatment Mass of bulbs (g) Productivity (t·ha-¹) T1 – Infested Control 19 d 4.50 d T2 – Weeded Control 50 a 11.47 a T3 – Pen¹, Pyr/Flu², Iox³, Pen 42 b 9.74 b T4 – Pyr/Flu, Pen, Iox, Pyr/ Flu 40 b 9.16 b T5 – Iox, Pen, Pyr/Flu, Iox 32 c 7.37 c T6 – Pen, Iox, Pyr/Flu, Pen 41 b 9.42 b T7 – Pyr/Flu, Iox, Pen, Pyr/ Flu 49 a 11.42 a T8 – Iox, Pyr/Flu, Pen, Iox 42 b 9.79 b T9 – Pyr/Flu, Pyr/Flu, Iox, Pyr/Flu 40 b 9.20 b T10 – Iox, Pyr/Flu, Pyr/Flu, Iox 36 b 8.44 b Coefficient of variation (%) 10.8 11.1 Table 5: Bulb mass and yield estimate considering the planting of 1,000 kg·ha-1 of ‘San Valentin’ garlic bulbs treated with differ- ent combinations of herbicides during crop development. São Marcos, UCS, 2022. ¹ – pendimethalin; ² – pyroxasulfone/flumioxazin; ³ – ioxynil. The adopted doses were 4.0 l·ha-1 for pendimethalin®, 0.15 l·ha-1 for pyroxa- sulfone/flumioxazin, and 1.5 l·ha-1 for ioxynil. DAA – days after appli- cation 4 - Considering the planting of 1,000 kg·ha-1 of bulbils. Means in column followed by the same letter do not differ statistically by the Scott-Knott test at a 5 % error probability. Source: Authors (2025). Acta agriculturae Slovenica, 121/2 – 2025 7 Efficacy and phytotoxicity of post emergence herbicides in garlic Furthermore, Mudge and Haller (2009) stated that her- bicides can cause crop toxicity, affecting development, growth, and productivity, as verified by 7 DAA of py- roxasulfone and flumioxazin when applied in corn, cot- ton, soybean, and wheat, begonia, impatiens, and snap- dragon. Therefore, the application of pyroxasulfone and flumioxazin principles in this period is not indicated. It is believed that this phenomenon occurred due to the size of the crop being more prominent and having a larger leaf area in this period. In this way, the contact of the formulations with the soil and weeds is reduced. The herbicide pendimethalin inhibits microtubule arrangement in mitosis, efficiently controlling annual grasses and specific broad leaves in pre-emergence. How- ever, this principle does not control established plants be- fore application (Chen et al., 2021). It was also possible to observe the control efficien- cy of pyroxasulfone/flumioxazin at 7 DAA, followed by ioxynil at 58 DAA, on wild carrot and speedwell regard- ing the other combinations tested. After application, the areas remained free of these weeds. According to the Sociedade Brasileira da Ciência das Plantas Daninhas (1995), a product must have a minimum control thresh- old of 80 % to be recommended for weed control of inva- sive species in that respective culture. Uzo and Currah (1990) pointed out that weeds can cause great productivity losses as they compete with the crop for space, nutrients, water, and light. In addition, invasive species can host diseases and release toxins/al- lelopathics that can inhibit or reduce crop development, thus decreasing final productivity. The increased competition pressure between the weeds and the culture may have caused a reduced bulb caliber. Luz et al. (2022) commented that when efficient weed control is not carried out, this can result in impor- tant yield losses for garlic crops. Most of the tested combinations showed satisfac- tory results for weed control, with emphasis on the py- roxasulfone/flumioxazin treatment at a dose of 0.15 l·ha-1 at 7 DAP (T7), which showed excellent control of weeds when applied to the garlic crop, not causing significant injuries due to phytotoxicity when compared to applica- tions at other stages of the crop. It was also noticed that, at 97 DAP where pyroxa- sulfone/flumioxazin was used, highlighting the combina- tion ioxynil, pyroxasulfone/flumioxazin, pyroxasulfone/ flumioxazin, and ioxynil (T10), the culture showed re- duced growth due to phytotoxicity concerning the con- trols (T1 and T2). Therefore, this product is not indicated in this period but in earlier periods, in which the leaf area of the crop is smaller. When using the pendimethalin herbicide in post- emergence of the crop, less phytotoxicity was observed in garlic in different application periods when compared to the pyroxasulfone/flumioxazin product, in addition to achieving excellent control of potato weed, lesser swi- necress, and speedwell. On the other hand, this product did not effectively manage wild carrot. The use of ioxynil at 7 DAP did not have reasonable control and produc- tivity results, making the ioxynil, pendimethalin, py- roxasulfone/flumioxazin, and ioxynil combination less effective than the other combinations assessed. Thus, the importance of applying pre-emergence herbicides at ear- lier crop stages is suggested to reduce the toxic effects on the garlic plants. 4 CONCLUSIONS The sequential application of pyroxasulfone/flumi- oxazin at 7 DAP, ioxynil at 58 DAP, pendimethalin at 97 DAP, and pyroxasulfone/flumioxazin at 128 DAP (T7) yielded the best results regarding the relationship be- tween phytotoxicity to the crop, weed control, and bulb classifications, presenting itself as an alternative to garlic producers, considering the current options for chemical control of weeds in the crop. 5 REFERENCES Abouziena, H. F., & Haggag, W. M. (2016). Weed con- trol in clean agriculture: a review. Planta Daninha, 34, 377-392. https://doi.org/10.1590/S0100- 83582016340200019 Alvares, C. 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