Spatial Distribution of Lissorhoptrus oryzophilus (Coleoptera: Curculionidae) in Rice

Abstract

Rice water weevil, Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae), is a destructive insect pest of rice in the United States. The pruning of rice roots by L. oryzophilus larvae can cause up to 25% yield loss. Currently, insecticidal seed treatments are used in the Louisiana rice industry as a pre-emptive means of controlling this weevil species. Our objective was to gain a better understanding of the spatial distribution of L. oryzophilus in Louisiana rice fields. Thirteen untreated commercial rice fields in Louisiana were mapped using GPS software, and surveyed for L. oryzophilus larvae over two years (2017 and 2018). An ANOVA, spatial interpolation, hotspot analysis, and multiple linear regression were used to determine where populations of L. oryzophilus were concentrated and whether distributions of the pest were related to edge effects. The results showed that L. oryzophilus larvae are typically aggregated along the edges of rice fields, with populations decreasing toward the center of rice fields. Lissorhoptrus oryzophilus densities were 3.3- and 2.2- fold greater along field edges than in field centers in 2017 and 2018, respectively. Hotspot spatial analysis revealed 59% and 32% of low-density clusters occurred at or near field centers, respectively. Multiple linear regression revealed larval densities decline with increasing distance from overwintering sites and alternative habitats (such as tree lines and levees containing bunch grasses and other alternative noncrop plants). These results suggest potential for insecticidal seed treatments to be applied selectively within rice fields to control this pest.

Distribution of Rice Plant Pests (Oryza sativa L.) in Vegetative and Generative Phases: analytical study

“…Various Plant Pest Organisms were found in rice cultivation activities since the vegetative and generative phases. This is in accordance with the report from Mulcahy et al (2022) that plant pest attacks cause damage to production yields to have a negative impact on both quality and quantity which is economically detrimental.…”

“…and the pink borer (Sesamia inference). According to Mulcahy et al (2022) that the most active planthoppers attacked were green leafhoppers (Nephotettix oryzae), brown leafhoppers (Nilaparvata lugens), white leafhoppers (Sogatella furcifer) and striped leafhoppers (Nephotettixapicalis) and green ladybugs (Nezara viridula) and rice hispa. (Diclandispa armigera)…”

Morphological Characteristics and Occurrence of an Important Stem-Boring Pest, Nassophasis sp. (Coleoptera: Rhynchophorinae)

“…Regarding distribution of Nassophasis sp., the insects were aggregated in the forest and shed, and the intensity of aggregation increased with increasing population density. This distribution pattern is the same as Lissorhoptrus oryzophilus [21], Anthonomus grandis [22], and Cosmopolites sordidus [23]. Upon analysis, the aggregation of Nassophasis sp.…”

Geostatistical Analysis of the Spatial Variation of Chrysolina aeruginosa Larvae at Different Stages in Desert Ecosystems

“…Since larvae do not migrate, the number of first and second instar larvae is greater in the center of the sample plot than at its edges. As the larvae mature, intra-specific competition increases, leading to a decrease in the population density of fourth instar larvae and a higher number of fourth instar larvae at the edge of the sample plot than at its center [19,[55][56][57][58].…”