TY - JOUR AU - Portuguez-García, Mary Pamela AU - Agüero-Alvarado, Renán AU - González-Lutz, María Isabel PY - 2020/09/01 Y2 - 2024/03/29 TI - Preemergence activity in the greenhouse on Arthraxon quartinianus, of an extract from Pinus sp. JF - Agronomía Mesoamericana JA - Agron. Mesoam. VL - 31 IS - 3 SE - Technical Notes DO - 10.15517/am.v31i3.39361 UR - https://revistas.ucr.ac.cr/index.php/agromeso/article/view/39361 SP - 773-779 AB - <p><strong><span class="CharOverride-2">Introduction.&nbsp;</span></strong>The pine extract may have herbicidal activity to other plants, affecting seed emergence.&nbsp;<span class="CharOverride-2"><strong>Objective.</strong>&nbsp;</span>To evaluate the pre-emergent effect of a&nbsp;<span class="CharOverride-6">Pinus</span>&nbsp;sp. extract in a greenhouse.&nbsp;<strong><span class="CharOverride-2">Materials and methods.</span>&nbsp;</strong>Two experiments were carried out in the K greenhouse of the Fabio Baudrit Moreno Agricultural Experimental Station (EEAFBM), Universidad de Costa Rica, the first in July and the second between September and October 2018. In the first one, the pre-emergent effect of pine extract, with and without added adherent to the spraying broth, on&nbsp;<span class="CharOverride-6">Arthraxon quartinianus (</span>A. Rich.) and a seed bank containing different species were evaluated; in the second experiment the pre-emergent effect of pine on&nbsp;<span class="CharOverride-6">Amaranthus</span>&nbsp;sp.,<span class="CharOverride-6">&nbsp;Ischaemum rugosum</span>&nbsp;Salisb., rice (<span class="CharOverride-6">Oryza sativa</span>), cucumber (<span class="CharOverride-6">Cucumis sativus</span>), and a seed bank was evaluated. For both experiments, a 15 % formulation of pine extract (3.75 kg a.i. ha<span class="CharOverride-9">-1</span>) was sprayed. In both experiments, the number of seedlings emerged was counted, in the first experiment it was recorded at nine days after spraying (das) and in the second at 17 das.&nbsp;<strong><span class="CharOverride-2">Results.&nbsp;</span></strong>The pre-emergent effect on broad-leaved species was not significant, but it was for&nbsp;<span class="CharOverride-6">A. quartinianus</span>&nbsp;(A. Rich.) (p=0,0009). The adherent reduced the effect of the pine extract on<span class="CharOverride-6">&nbsp;A. quartinianus</span>&nbsp;(A. Rich.) (p=0,0116) and other species (p=0,0398). There was an increase in the germination of weeds coming from the seed bank, 121 % for broad-leaved species in general, 92 % for&nbsp;<span class="CharOverride-6">Amaranthus&nbsp;</span>sp. (p=0,013). Besides, the adherent increased the germination of rice seeds by 34 % (p&lt;0,0001).&nbsp;<strong><span class="CharOverride-2">Conclusions.</span>&nbsp;</strong>In a greenhouse there was only a significant pre-emergent effect of pine for the weed&nbsp;<span class="CharOverride-6">A. quartinianus</span>&nbsp;(A. Rich.). The pine extract increased the germination of several species.</p> ER -