Diaphania indica | Pest Rating Proposals and Final Ratings

California Pest Rating for

Cucumber Moth | Diaphania indica (Saunders)

Lepidoptera: Crambidae

Pest Rating: A

PEST RATING PROFILE

Initiating Event:

Diaphania indica is currently Q-rated. A permanent pest rating proposal is required to support an official pest rating.

History & Status:

Background: Diaphania indica is a pest of cucurbit crops, including cucumber, melon, and watermelon. It has also been reported to feed on plants in the families Fabaceae and Malvaceae (Arcaya et al., 2004; Ganehiarachchi, 1997; MacLeod, 2005). Adults have a wingspan of 24-33 mm. The hind and forewings have solid white centers and thick, brown margins (Evaratt et al., 2015). Eggs are laid on the undersides of leaves. The larvae feed on leaves as well as flowers and fruits (Ganehiarachchi, 1997; Kinjo and Arakaki, 2002). This moth is mostly restricted to tropical and subtropical climates. For example, in the United States, it is only found in Florida. However, it has become a pest in greenhouses in Japan and Korea, and it may be capable of living in more temperate climates in these situations (Kinjo and Arakaki, 2002; MacLeod, 2008).

Worldwide Distribution: Diaphania indica is native to the Old World tropics (Waterhouse, 1993). It is reported from tropical and subtropical areas in Africa, Australia, the Middle East, Asia, Pacific islands, Central America, South America, and the southeastern United States (only in Florida) (Clavijo A., 1990). There are a few records from Alabama and Texas, but these may not represent established populations (Symbiota Collections of Arthropods Network).

Official Control: Diaphania indica is considered reportable by the United States Department of Agriculture.

California Distribution: Diaphania indica is not known to occur in California.

California Interceptions: Diaphania indica has been intercepted on mango fruit from Florida (PDR # 430P06135915).

The risk Diaphania indica would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: The distribution of Diaphania indica appears to be largely restricted to areas with a tropical or subtropical climate. It is possible that it could become established in a limited portion of California. Therefore, Diaphania indica receives a Low (1) in this category.

– Low (1) Not likely to establish in California; or likely to establish in very limited areas.

– Medium (2) may be able to establish in a larger but limited part of California.

– High (3) likely to establish a widespread distribution in California.

2) Known Pest Host Range: Diaphania indica feeds on a variety of crop plants in three families. Therefore, it receives a Medium (2) in this category.

– Low (1) has a very limited host range.

– Medium (2) has a moderate host range.

– High (3) has a wide host range.

3) Pest Dispersal Potential: Diaphania indica Eggs or larvae could be moved with infested plants. Therefore, it receives a Medium (2) in this category.

– Low (1) does not have high reproductive or dispersal potential.

– Medium (2) has either high reproductive or dispersal potential.

– High (3) has both high reproduction and dispersal potential.

4) Economic Impact: Diaphania indica feeds on a variety of crops in the family Cucurbitaceae, causing loss of fruit and plant mortality. This species has achieved pest status both in fields as well as in greenhouses. Therefore, it receives a Medium (2) in this category.

Economic Impact: A, B

A. The pest could lower crop yield.

B. The pest could lower crop value (includes increasing crop production costs).

C. The pest could trigger the loss of markets (includes quarantines).

D. The pest could negatively change normal cultural practices.

E. The pest can vector, or is vectored, by another pestiferous organism.

F. The organism is injurious or poisonous to agriculturally important animals.

G. The organism can interfere with the delivery or supply of water for agricultural uses.

Economic Impact Score: 2

– Low (1) causes 0 or 1 of these impacts.

– Medium (2) causes 2 of these impacts.

– High (3) causes 3 or more of these impacts.

5) Environmental Impact: There are native California plants in the family Cucurbitaceae. It is possible that, if established, Diaphania indica could disrupt natural communities where these plants occur. Crop infestations could trigger treatments. Therefore, it receives a High (3) in this category.

Evaluate the environmental impact of the pest on California using the criteria below.

Environmental Impact: A, D

A. The pest could have a significant environmental impact such as lowering biodiversity, disrupting natural communities, or changing ecosystem processes.

B. The pest could directly affect threatened or endangered species.

C. The pest could impact threatened or endangered species by disrupting critical habitats.

D. The pest could trigger additional official or private treatment programs.

E. The pest significantly impacts cultural practices, home/urban gardening or ornamental plantings.

Score the pest for Environmental Impact. Score:

Environmental Impact Score: 3

– Low (1) causes none of the above to occur.

– Medium (2) causes one of the above to occur.

– High (3) causes two or more of the above to occur.

Consequences of Introduction to California for Diaphania indica: Medium (10)

Add up the total score and include it here.

–Low = 5-8 points

–Medium = 9-12 points

–High = 13-15 points

6) Post Entry Distribution and Survey Information: Diaphania indica is not known to occur in California. It receives a Not established (0) in this category.

–Not established (0) Pest never detected in California, or known only from incursions.

–Low (-1) Pest has a localized distribution in California, or is established in one suitable climate/host area (region).

–Medium (-2) Pest is widespread in California but not fully established in the endangered area, or pest established in two contiguous suitable climate/host areas.

–High (-3) Pest has fully established in the endangered area, or pest is reported in more than two contiguous or non-contiguous suitable climate/host areas.

Final Score:

7) The final score is the consequences of introduction score minus the post entry distribution and survey information score: Medium (10)

Uncertainty:

There is no uncertainty regarding the potential of Diaphania indica to be a pest in the right environment. However, there is significant uncertainty regarding its ability to become established in California, as this species is apparently restricted to tropical/subtropical climates (except for greenhouses).

Conclusion and Rating Justification:

Diaphania indica is a pest of cucurbit crops and it is not known to occur in California. It is possible that it could become established over a limited portion of the state, and if this occurred, this species could have economic and environmental impacts. For these reasons, an “A” rating is justified.

References:

Arcaya S., E., Díaz B., F., and Paz L., R. 2004. Primer registro de Diaphania indica (Saunders, 1851) (Lepidoptera: Crambidae) en el cultivo de pepino en Venezuela. Bioagro. 16(1): 73-74.

Clavijo A., J.A. 1990. Systematics of black and white species of the genus Diaphania Hubner (1818) (Lepidoptera: Pyralidae: Pyraustinae). Ph.D. thesis. McGill University. 215 pp.

Evaratt, M., Korycinska, A., and C. Malumphy. 2015. Plant pest factsheet; cucurbit moths; Diaphania species. Department for Environment Food & Rural Affairs.

Ganehiarachchi, G.A.S.M. 1997. Aspects of the biology of Diaphania indica (Lepidoptera: Pyralidae). Journal of the National Science Council of Sri Lanka. 25(4): 203-209.

Kinjo, K. and N. Arakaki. 2002. Effect of temperature on development and reproductive characteristics of Diaphania indica (Saunders) (Lepidoptera: Pyralidae). Applied Entomology and Zoology. 37(1): 141-145.

MacLeod, A. 2005 (revised). Pest risk analysis for Diaphania indica. Department for Environment, Food and Rural Affairs: Central Science Laboratory.

Symbiota Collections of Arthropods Network (SCAN). Accessed March 6, 2018. http://symbiota4.acis.ufl.edu

Waterhouse, D.F. 1993. The Major Arthropod Pests and Weeds of Agriculture in Southeast Asia: Distribution, Importance and Origin. Australian Center for International Agricultural Research. 141 pp.

Author:

Kyle Beucke, 1220 N Street, Room 221, Sacramento, CA, 95814, 916-403-6741, plant.health[@]cdfa.ca.gov

Responsible Party:

Jason Leathers, 2800 Gateway Oaks, Sacramento CA 95833, (916) 654-1211, plant.health[@]cdfa.ca.gov

Comment Period:* CLOSED

3/15/18 – 4/29/18

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