Host Testing and Environmental Assessment of Anaphes nipponicus, a New Natural Enemy of the Cereal Leaf Beetle

Transcription

1 Host Testing and Environmental Assessment of Anaphes nipponicus, a New Natural Enemy of the Cereal Leaf Beetle Final Report: April, 2009 Terry D. Miller, Department of Entomology, FSHN 166, Pullman, WA Phone: FAX: tdmiller@wsu.edu Diana Roberts WSU Extension, 222 N Havana St., Spokane WA Phone: robertsd@wsu.edu Project Objectives 1. Receive Asian parasite material into quarantine 2. Perform quarantine screening 3. Perform host range identification 4. Determine temperature requirements for development of parasite Work Accomplished 1. Receive Chinese parasitoid material Barry Bai of the Oregon Department of Agriculture working with the USDA-ARS Sino- American Biocontrol Lab in Beijing and local contacts in Province collected the rice leaf beetle, Oulema oryzae, eggs parasitized by A. nipponicus in May 2007 for shipment to quarantine at Washington State University (WSU). The local collaborators in Province continued to collect parasitoids later during the 2007 season after Dr. Bai had left the area and continued collecting during May/June of 2008 for shipment to the WSU quarantine. The US/China team collected Anaphes nipponicus mainly from Fuzhou area. Collaborators in Provincecontinuously collected in seven counties around Fuzhou area. About 15 field collection trips were made during the 2007 season and 8 during Four shipments of parasitized rice leaf beetle eggs were sent to Washington State University s quarantine facility for further screening and host range/non-target testing in 2007 and three in Each shipment contained up to a few hundred rice leaves with the leaf beetle eggs. 2. Quarantine screening Quarantine officer and facility technician conducted quarantine screenings of received materials as they came into the facility, separating the A. nipponicus from potential contaminants.

2 2007 Shipment #1 6/5/07 left Dr. Lin s lab 6/11/07 received at WSU All samples are very wet and covered in fungi/bacteria. Yongtai, Fuzhou - 0 wasps/beetles emerged collected: 2007 May 20 Fuging, Fuzhou - 0 wasps/beetles emerged collected: 2007 May 19 Fuging, Fuzhou - 0 wasps/beetles emerged collected: 2007 May 25 Chengle, Fuzhou - 0 wasps/beetles emerged collected: 2007 May 22 Yongtai, Fuzhou - 0 wasps/beetles emerged collected: 2007 May Shipment #2 6/11/07 left Dr. Lin s lab 6/18/07 received at WSU This shipment looks better, the eggs look alive and healthy although there was heavy ammonium smell from the bag (probably due to poor ventilation) and moisture. Ningning, Fuzhou - 0 wasps/beetles emerged collected: 2007 June 4 Beifeng, Fuahore - 0 wasps/beetles emerged collected: 2007 June Shipment #3 6/15/07 left Dr. Lins lab

3 6/21/07 received at WSU this shipment is still too wet but better than last one. Dahu, Minhou - 0 wasps/beetles emerged collected: 2007 June 12 Yangli, Minhou - 0 wasps/beetles emerged collected: 2007 June Shipment #4 6/20/07 left Dr. Lin s lab 6/25/07 received at WSU Shipment best looking so far. Moisture present but minimal. Wasps have just started to emerge on arrival Tangchuan, Youxi - 24 wasps emerged (10 female, 14 male) Province collected: 2007 June 14 Zhanghuban, Nanping - 15 wasps emerged (8 female, 7 male) Province collected: 2007 June Shipment #1 shipped USPS global express mail Shipped 5/26/08 Received 6/04/08 5/10/08 collection - (2 female, 1 male) QingKou, Minhou Fuzhou, 5/13/08 collection - (61 female, 38 male) Bannzhong, Minqing Fuzhou, 5/ 25/08 collection - (1 female, 2 male) Dongzhang, Fuqing

4 Fuzhou, Shipment #2 shipped USPS global express mail The second shipment has yielded few wasps. It appears many succumbed to some kind of fungus or bacteria that is causing liquefaction of the eggs. Dr. Lin noted that rice fields were being sprayed late May in the area. Shipped 6/02/08 Received 6/09/08 5/31/08 collection - (0 emergence) Wutong, Yongtai Fuzhou, 6/1/08 collection - (5 female, 2 male) Huangxi, Jinquan Fuzhou, Shipment #3 shipped USPS global express mail The third shipment has yielded no wasps. It appears many succumbed to some kind of fungus or bacteria that is causing liquefaction of the eggs. Dr. Lin noted that rice fields were being sprayed late May in the area. Shipped 6/13/08 Received 6/19/08 6/3/08 collection - ( 0 emergence) Dahu, Minhou Fuzhou, 6/6/08 collection - (0 emergence) Huangxi, Jinquan Fuzhou, 6/9/08 collection - ( 0 emergence) Tangehuan, Youxi Sanmin, Objective 3. Host range identification Determine alternate host range of A. nipponicus. In its native range in Asia, it is found on Lema oryzae and Oulema oryzae feeding on rice. We will test A. nipponicus on cereal leaf beetle eggs as well as Lema trilinea trivittata eggs. These are the only two species in these genera in the Pacific Northwest of the U.S. Method : 20 C 75%RH, 16:8 light-cycle

5 No choice test using CLB and 3-lined potato beetle eggs. Twenty-five female wasps were exposed to each of the 2 potential host eggs. Five 1 day old CLB eggs were inserted each day till death.of the A. nipponicus Each parasitoid was provided with 30 target eggs. All target eggs were <48 hrs of age. In all tests, the parasitoids were provided with honey water (%?) as a food source and allowed 24 h to parasitize eggs before they were removed from the test arena. Results : Anaphes nipponicus showed little interest and was unable to successfully attack Lema trilinea trivittata eggs. Anaphes nipponicus upon presentation of cereal leaf beetle eggs readily attacked, oviposited and successfully completed two generations on CLB eggs. Objective 4. Determine temperature requirements for development of parasite Method : Twenty-five male and female wasps were placed in environmental chambers maintained at 15, 20 and 30 C at both 25% RH and 75% RH Results : At 15 C and 75% RH the adults emerge from the host egg in 32 days. 17/25 emerged ( 7 male, 10 female) At 15 C and 25% RH the no adults emerged from the host eggs. At 20 C and 75% RH the adults emerge from the host egg in 11 days. 22/25 emerged (9 male, 13 female) At 20 C and 25% RH no adults emerged from the host eggs At 30 C and 75% RH the adults emerge from the host egg in 8 days. 20/25 emerged (8 male, 12 females) At 30 C and 25% RH no adults emerged from the host egg A. nipponicus requires higher humidity levels for development. Similar to what is found in rice fields in China. No development of A. nipponicus at 25% RH. This relative humidity level is representative of field humidity levels in eastern

6 Washington. Objective 5 - Build population of A. nipponicus Five resultant females from experiments were exposed to CLB for one more generation in 2007 till supplies of CLB eggs were depleted. Ten mated females were used to propagate one additional generation in 2008 till field and lab supplies of cereal leaf beetle were depleted. Readily available supplies of CLB eggs is the limiting factor in continued propagation of this wasps. Inducing diapause in Anaphes might be one way to keep cultures going without available host eggs in the fall and winter. It is not known whether or not Anaphes nipponicus enters diapause in southern China. Summary The long delay in getting APHIS and Chinese permits hindered our ability to get good quality materials collected when Dr. Bai was in China in Our first three shipments from China in 2007 were all shipped at the end of wasp development and were held too long before shipment to the U.S. which led to a degradation of host plant material in transit that led to complete mortality. The fourth shipment of material was collected and sent ASAP and arrived in much better condition. A total of 39 parasitic wasps emerged from this shipped material. In 2008 we had eight collections from Province spread over three shipments from mid May to mid June. The first two collections in early May were the only samples to yield wasps in any numbers. Rice fields in the vicinity of later collections were treated with insecticides in late May and early June. This is the probable cause of mortality with these collections. A. nipponicus will readily attack CLB eggs in the quarantine facility and successfully completed two generations on the CLB eggs. A. nipponicus is unable to develop at low relative humidities as would be found in eastern Washington. This species showed no interest in Lema trilinea trivittata eggs, only successfully attacking CLB eggs. Anaphes nipponicus has no potential as a biological control agent against CLB in eastern Washington but may survive at lower latitudes with higher humidity.