Mexican Rice Borer Control Tactics in United States Sugarcane

Abstract

The invasive Mexican rice borer, Eoreuma loftini (Dyar), expanded its range from Mexico to South Texas in the early 1980s. By 2008 the pest had moved into sugarcane- and rice-growing areas of East Texas and Louisiana, and by 2012 it was reported on noncrop host plants in Florida. Efforts to suppress E. loftini in United States sugarcane with chemicals and biological control agents were unsuccessful, so both tactics were discontinued, and E. loftini infestation of sugarcane has continued unchecked. During the last 15 years, however, research has focused on the pest’s ecology, improved insecticides and scouting methods, the identification of sugarcane resistance mechanisms, and new cultural tactics. A surveillance technique was developed that indicates when larvae are most vulnerable to insecticide sprays. Currently, registered insecticides for E. loftini control are not widely applied, although some show promise, including an insect growth regulator. A number of potentially useful cultural practices are available, including plowing under fallow stubble, judicious use of fertilizer, adequate irrigation, avoiding proximity to E. loftini-susceptible maize cultivars, and enhancement of natural enemy populations. Demonstrated and potentially useful sugarcane resistance mechanisms involve physiochemical attributes, physical characteristics, and transgenic cultivars.

Resistance to Diatraea (Lepidoptera: Crambidae) stem borers in sugarcane is independent of species

“…Discrepancies may be found between levels of resistance found using plant injury and those found using survival to adulthood (Bessin et al 1990b, Reay-Jones et al 2003). The Relative Resistance Ratio (RRR) index of Wilson et al (2015) with E. loftini could be considered to be groundbreaking, as was suggested by Showler (2019), since it includes plant injury and insect biology in one variable. However, it has also been argued that when using RRR, there should be a greater number of varieties than those examined in the present study to be able to establish contrast between genotypes.…”

Lignocellulosic Composition Not Associated with Stem Borer Resistance in Select Louisiana Sugarcane Cultivars

“…In Louisiana, the sugarcane borer (SCB; Diatraea saccharalis (Fabricius); Lepidoptera: Crambidae) is considered the primary insect pest, with an estimated economic impact of USD 8.0 million annually [5]. The other primary insect pest of concern is the Mexican rice borer (MRB; Eoreuma loftini (Dyar); Lepidoptera: Crambidae) [4,6,7], which was first documented in sugarcane growing areas of the Lower Rio Grande Valley (LRGV) in south Texas in the 1980s [8]. By 2008, MRB had spread north along the Texas Gulf Coast [9,10] and into Louisiana [11].…”

Characterization of Resistance to the Mexican Rice Borer (Lepidoptera: Crambidae) among Sugarcane Cultivars

“…The most important insect pests of sugarcane in Louisiana and Texas (USA) are the stem borer complex [ 2 , 3 ], which is formed by two species of the family Crambidae (Lepidoptera). The primary pest historically has been the sugarcane borer ( Diatraea saccharalis (F.)), which is decreasing in importance [ 4 ].The emerging threat is the invasive Mexican rice borer, Eoreuma loftini (Dyar) [ 3 , 5 ], which is expected to increase economic losses caused by insects significantly once it has become established throughout Louisiana [ 5 , 6 , 7 ]. Since 2008, E. loftini has been spreading northward and eastward into Louisiana’s sugarcane and rice production regions, with infestations becoming more frequent in recent years [ 8 , 9 ].…”

“…One of the most promising management tactics for E. loftini is cultivar resistance. Cultivars with documented resistance to D. saccharalis have greatly improved IPM success and reduced reliance on chemical controls methods in Louisiana sugarcane [ 4 , 5 , 16 , 17 ]. Cultivar resistance is particularly compatible with stem borer IPM because resistant cultivars that delay stalk entry enhance larval exposure to insecticides and natural enemies [ 14 ].…”