Surface properties of Tetranychus urticae Koch (Acari: Tetranychidae) and the effect of their infestation on the surface properties of kidney bean (Phaseolus vulgaris L.) hosts

Abstract

BACKGROUND The wettability of the target surfaces affects the wetting and deposition of pesticides on them. The properties of leaf surfaces change after infestation by Tetranychus urticae Koch. Studying the surface wettability of T. urticae and the changes in leaf wettability after infestation is important to guide the use of acaricides. RESULTS The body surface of T. urticae is an ellipsoidal crown covered with dense cuticle striations and hairs arranged in different directions, which makes the surface of T. urticae rough and hydrophobic. The abaxial surfaces of the leaves are rougher and more hydrophobic than the adaxial surfaces. After infestation by T. urticae, the faded spots were sunken on the adaxial surface and raised on the abaxial surface, where they had formed new wide peaks and valleys. The adaxial surface became obviously rougher and more hydrophobic, while the roughness of the abaxial surface became slightly larger, and the change in hydrophobicity was not obvious. The contact angles of the studied commercial acaricide on these surfaces were greater than 65° and were affected by the infestation. Reducing the surface tension can allow for better wetting of these surfaces and eliminate changes in leaf wettability. CONCLUSION The surfaces of kidney bean leaves became more hydrophobic after infestation by T. urticae with hydrophobic surface. The wettability of the acaricide solution should be adjusted according to the changes in leaf wettability. This study has important theoretical guiding significance for improving effective deposition of acaricide.

The effect of Aceria litchii (Keifer) infestation on the surface properties of litchi leaf hosts

“…The spore mass of erineum was transformed into powdered form, and the physical structure of these powdered erineums changed, and the loose structure increased the surface wettability, which promoted their attachment to rain and surrounding air, 37 thus accelerating the spread of the disease, which explains the phenomenon that the wettability increased instead as the infestation stage progressed, and which explains the further decrease in the contact angle in the third stage mentioned above. These findings are consistent with previous studies of powdery mildew on brassicas, cucumbers, and wheat, and provide a complementary perspective on how pests and diseases alter plant surface properties 28–30 …”

“…These findings are consistent with previous studies of powdery mildew on brassicas, cucumbers, and wheat, and provide a complementary perspective on how pests and diseases alter plant surface properties. [28][29][30] The foliar attributes of plants constitute fundamental factors that exert a profound influence on the wettability of their leaf surfaces. While modifying these foliar properties to improve pesticide dispersion remains an unattainable goal, developing a comprehensive understanding of the alterations in plant foliar wettability assumes paramount importance.…”

“…The polarity and surface tension characteristics of the selected test liquids follow the hierarchical order of water > formamide > ethylene glycol, this sequence adheres precisely to the testing prerequisites articulated by the WORK method, a methodology hitherto successfully applied in the assessment of surface properties pertaining to leaves of rice, pear, and kidney bean. 25,28,34 Based on the CA measurements, the SFE of litchi leaves at various stages of infestation by Aceria litchii, along with its dispersion component and polarity component, were computed. This analysis was conducted using the OWRK method and the SFE calculation software integrated into CAPST-2000At.…”

“…Lu et al found by focus change microscopy that brassica leaves infested with urticating nightshade moths had enhanced surface hydrophobicity. 28 He et al classified powdery mildew growth into four stages based on surface texture characteristics of diseased cucumber leaves, and subsequently investigated the surface texture and wettability of cucumber powdery mildew leaves, offering valuable insights. 29 Building upon this, Song et al conducted investigations concerning the interfacial interactions of pesticide droplets with the surfaces of infected wheat powdery mildew leaves.…”

“…Lu et al . found by focus change microscopy that brassica leaves infested with urticating nightshade moths had enhanced surface hydrophobicity 28 . He et al .…”