Ecology and pest status of Mussidia nigrivenella Ragonot (Lepidoptera: Pyralidae), a cob borer of maize in West Africa

[no abstract

Spatio-Temporal Distribution of Ceratothripoides claratris (Thysanoptera: Thripidae) on Tomatoes in Thailand

Ceratothripoides claratris Shumsher is one of the most important thrips pest of tomatoes in central Thailand. Hence we conducted studies to determine the intra- and inter-plant distribution of C. claratris on tomatoes in two types of greenhouses, i.e., open-plastic and closed net house. The experiments were conducted on the campus of the Asian Institute of Technology in Bangkok, Thailand. Both adults and larvae of C. claratris showed foliage-biased distribution. Sex ratios of adult C. claratris did not significantly differ on flowers and leaves, whereas on fruits males significantly outnumbered females. On flowers, no diurnal periodicity of occurrence of C. claratris was detected. Generally, thrips infestation commenced in the lower parts of the tomato plants and gradually spread to the higher strata of the plants. Depending on the greenhouse type and the stem system thrips infestation differed significantly over time in the lower but not in the uppermost strata of the plants. In the net house, infestations of C. claratris commenced one week after planting of the tomato seedlings. Soon after the peak in infestations, thrips numbers dramatically decreased. Estimates of Taylor’s power showed that C. claratris had an aggregated distribution pattern on the foliage of tomato plants. The importance of these findings for future monitoring programs of C. claratris infestations on tomatoes is discussed

Wheat Curl Mite: A New Source of the Eriophyoid Mite in Wheat Fields Identified

Wheat curl mites (WCMs; Aceria tosichella) are an important global pest of cultivated wheat. Their feeding activities on epidermal cells of wheat leaves result in characteristic leaf curl symptoms that prevent the unfurling of affected leaves and impair the proper emergence of heads from the boot stage. The most significant economic impact of WCM infestation, however, is their ability to vector and transmit four important viruses of wheat, specifically, wheat streak mosaic virus, Triticum mosaic virus, High Plains wheat mosaic emaravirus, and brome streak mosaic virus. Being wingless, WCMs are almost completely dependent on air currents for their dispersal. In addition, because of their obligate lifestyle, wheat field infestations are thought to originate from sources such as volunteer wheat. Corn and other cultivated and noncultivated Poaceae hosts are also known to act as green bridges between successive wheat crops. Consequently, management practices mostly target these off-season host plants but also the use of resistant varieties and other cultural control methods. Here we report the discovery of seed-borne WCM eggs, a previously unknown method of their dispersal, as a possible source of new infestations in wheat fields. This discovery expands our understanding of the biology of WCMs, with potential implications for the development of more holistic and effective management strategies for this economic pest and virus vector. [Graphic: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY 4.0 International license

Spatial niche selection indices for <i>D</i>. <i>citri</i> adults in three habitat types in commercial citrus groves in South Texas (2009–2012).

<p>¹<i>W</i>_i = selection index of <i>D</i>. <i>citri</i>; Selection indices followed by the same letter are not significantly different at P = 0.05 (log-likelihood ratio [G] test).</p><p>²<i>B</i>_<i>i</i> = standardized selection index for <i>D</i>. <i>citri</i>; standardized selection indices of (1/number of habitats), or 0.33 in this case, indicate no preference. Values above 0.33 indicate relative preference, and values below 0.33 indicate relative avoidance.</p><p>Habitat types are represented by perimeter, adjacent and interior trees.</p

Mean number of <i>D</i>. <i>citri</i> life stages per flush shoot and percent flush infestation level in relation to tree location in grapefruit and sweet orange groves during area-wide surveys (2009–2010).

<p>Mean number of <i>D</i>. <i>citri</i> life stages per flush shoot and percent flush infestation level in relation to tree location in grapefruit and sweet orange groves during area-wide surveys (2009–2010).</p

<i>Diaphorina citri</i> flush shoot infestation levels and population fluctuations on citrus trees depending on their position in the grove during area-wide surveys (2009–2010).

<p><i>Diaphorina citri</i> flush shoot infestation levels and population fluctuations on citrus trees depending on their position in the grove during area-wide surveys (2009–2010).</p

Mixed model analysis of variance showing <i>F</i>-values¹ of major parameters affecting <i>D</i>. <i>citri</i> densities and infestation levels in mature citrus groves in Texas (2009–2010).

<p>Error df for all analysis = 35,000.</p><p>¹ ns = non-significant (P>0.05).</p><p>** = highly significant (P < 0.01).</p><p>Mixed model analysis of variance showing <i>F</i>-values<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0131917#t001fn002" target="_blank">¹</a> of major parameters affecting <i>D</i>. <i>citri</i> densities and infestation levels in mature citrus groves in Texas (2009–2010).</p

Exponential decay function (<i>y</i> = <i>a</i>*<i>exp</i> [<i>-bx</i>]) describing the decrease in <i>D</i>. <i>citri</i> densities and infestation levels from the edge to the interior of the grove in area-wide surveys.

<p>Exponential decay function (<i>y</i> = <i>a</i>*<i>exp</i> [<i>-bx</i>]) describing the decrease in <i>D</i>. <i>citri</i> densities and infestation levels from the edge to the interior of the grove in area-wide surveys.</p