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Building an Area-Wide IPM Perspective for Stalk Borers Threatening Sugarcane and Rice

Investigators
Reagan, Thomas
Institutions
Louisiana State University
Start date
2008
End date
2011
Objective
The program goals focus on the multi-disciplinary management of stalk borers, primarily the invasive alien species Mexican rice borer (MRB), and the sugarcane borer (SCB), in sugarcane and rice. The proposal mandates more of a landscape approach to IPM, emphasizing selected non-crop hosts (at least during certain times of the year), and late season cultural practices combined with a more creative use of environmentally-friendly insecticides to reduce area-wide pest populations.

Consistent with these goals, the stated objectives designed to further develop and implement an IPM program to reduce area-wide stalk borer pest populations and minimize sugarcane/rice FQPA-related constraints are:

  1. To develop a landscape approach to the role of non-crop host plants impacting sugarcane and rice systems involving - a. Sentinel plant and multi-area transect studies (MRB/SCB), b. Host preference and survival with non-crop hosts, and c. Phenological surveys of crops/surveys of field margins (TX/LA).
  2. To compare selected sugarcane and rice production practices as impacting potentially overwintering stalk borer populations and damage.
  3. To assess novel chemistry as improved insecticidal management alternatives to FQPA-threatened insecticides, and appropriately modify needed resistance management plans.
Potential management of the MRB and expected outputs of the program will come partially from the continuing development and production of resistant varieties to MRB and SCB in both sugarcane and rice. The potential for area-wide pest reduction will likely rely also on effective management of certain weed hosts to be identified in this study.

It is expected that careful management of only one or two weed species, maybe for only 6 to 8 weeks in the year, could greatly reduce one of these stalk borer pests. New insecticides such as novaluron and rynaxypyr will likely play an important role in rice management of MRB and SCB. However, if the sugarcane industry can utilize rynaxypyr for wireworm control and achieve a 1.5 to 2 month residual (systemic) for SCB/MRB similar to what has been shown in rice, a very dramatic and lasting management can be foreseen (especially because of the protection of beneficial arthropods).

Cultural practices to minimize sugarcane stress are already showing an important role in MRB management. The manipulation of planting date (sugarcane) and enhancing vigor in ratoon rice will also be important to reduce crop/pest synchrony. These results will be the cornerstone of a proactive, effective IPM program for stalk borers attacking sugarcane and rice in Texas and Louisiana.

Because of the impact in reducing area-wide pest populations, the economic productivity of other crops (including for bioenergy) such as corn and sorghum is expected to be enhanced. As such, it is anticipated that our program could serve as a model for area-wide pest management. An integral component of the proposal is stakeholder input and direct involvement in the performance and evaluation of the research objectives.

More information
Non-Technical Summary: The Mexican rice borer (MRB), Eoreuma loftini (Dyar) and the sugarcane borer (SCB), Diatraea saccharalis (F.) are serious pests of sugarcane and rice. Since MRB was introduced from Mexico in 1980, it has spread northward through the Texas Rice Belt and now threatens the Louisiana sugarcane and rice industries. MRB and SCB have become the key pest complex of Texas Gulf coast rice, with insecticide use approaching three applications, annually. Sugarcane and rice generate over $2.5 billion annually for Texas and Louisiana stakeholders, but these commodities are at risk from this new pest complex and usage restrictions, mandated by FQPA, on organophosphate (OP) insecticides. Eventual annual losses of $220 million in sugarcane and $45 million in rice due to MRB invasion would be expected based on current production practices. We propose to solve the problems of our stakeholders by developing and implementing a diversified, proactive stalk borer IPM program which will be expected to mitigate sugarcane/rice potential FQPA-related constraints and reduce stalk borer populations. Within season management progress emphasizes cultivar resistance, minimizing plant stress, and timely use of insecticides. This proposal mandates more of a landscape approach to IPM focusing on selected non-crop hosts (at least during certain times of the year), and late season cultural practices combined with a more creative use of new environmentally-friendly insecticides to reduce area-wide pest populations. The significance to bioenergy, including corn and sorghum, is also noted. An integral component of the proposal is stakeholder input and direct involvement in the performance and evaluation of the research objectives.

Approach: Research assessing the role of various species of weeds as alternate hosts in SCB/MRB population dynamics will involve 4-rep sentinel plant experiments, paired treatment studies among different habitats, and greenhouse oviposition studies. Transect studies will be conducted in the lower, middle, and upper regions of the Texas rice belt. Weed phenological surveys will also be conducted in the Texas rice belt, South Louisiana rice and sugarcane areas. For the sentinel plant studies, weeds will be grown for 8 weeks in a greenhouse prior to being carried and transplanted in a rice field. Destructive sampling conducted at 30 and 60 days post-transplant will assess natural borer density, speciation, and stage. For oviposition preference estimation, preference coefficients for a given host on a per tiller, per plant, or per gram of host mass will be derived using previously published equations. When combined with estimates of relative host availability, preference coefficients will be developed to obtain the relative oviposition selection for each host. In order to determine the role of planting date interacting with varietal resistance on future pest populations in sugarcane, a 5-rep two year field study will be conducted in two areas with SCB-susceptible and resistant cultivars in four planting dates. Assessment of infestation and SCB production for potential overwintering will involve periodic destructive samplings and deadheart comparisons in the Fall and Spring. For Objective 3 involving novel chemistries as interacting with cultural practices to replace FQPA-threatened insecticides, experiments will be conducted at Ganado, TX where stalk borer populations typically are high and damaging. Dermacor X-100 will be tested at different rates with a minimum of 4 treatments with 4 reps in a RCB design. When rice reaches milk/soft dough, whiteheads will be counted in the middle 4 rows of each plot. At maturity, plots will be harvested and yields recorded. None of the ratoon plots will be treated for stalk borers; but, whitehead counts and yields will be taken as in the main crop. Additional experiments will be conducted on sandy loam (high wireworm infestations) soils in heavy SCB infestation areas of sugarcane in Louisiana. These studies will assess the potential role of rynaxpyr in soil insect management, preserving beneficial arthropods (monitoring with pitfall traps), and assessing the possible residual impact if any, on stalk borers. In addition, a 5- rep small plot test will be conducted to assess stalk borer management from foliar applications. Evaluation of project success, including refereed and non-refereed publications will include responses to meeting questionnaires. Also, comparisons of % adoption of practices by producers in different counties and parishes each in Texas and Louisiana will assess adoption of cutting height recommendations, use of new insecticides, and stakeholder knowledge of weed management. Plans to work with county agents in conducting spot surveys of % whiteheads (year 1 vs. year 2) and % bored internodes will provide pest population density comparisons.

Funding Source
Nat'l. Inst. of Food and Agriculture
Project source
View this project
Project number
LAB03919
Accession number
214678
Categories
Risk Assessment, Management, and Communication
Chemical Contaminants
Commodities
Grains, Beans, Legumes