Proceedings of the 7th Iniernatumal Working Conference on Stored-product Protection. - Volume 2

Study on relationship of infestation of the Angoumois grainmoth, Sitotroga cereallela (Lepidoptera: Gelechiidae), towheat cultivars

Wu JunXiangl and Duan Yongf'eng/

Abstract

Relationship of infestation of the Angoumois gram moth(AGM) , Sttotroga cereallela (Ohvier ) to wheat cultrvarswas prehmmanly dealt with. Results showed that therewere no significantly statistical differences of the rates ofegg-deposited grams or the egg numbers on 100 grams in 10wheat cultrvars. Development penods and survival ratesduring development from egg to moth of AGM or rates ofinfested grams and loss rates of infested grams m vanouswheat cultrvars displayed differences to some degrees, but,these differences were not proved in statistics due to fewersamples in the experiment. More works need to be carriedout further m order to clarify that the differences are sure ornot. Relativity analysis showed that the interrelation ofpreference of AGM to antibiosis of wheat cultrvar was notstatistically significant.

Introduction

The Angoumois gram moth (AGM) , Sitotroga cereallela( Olivier ), 1S one of the most important pest insectsdiscovered in stored cereal grain in all over the world. Itinfested mainly the stored wheat m barn in central andnorthern China. It was reported that the water contents,free amino acids and uric acids were increased and the 1000grain weights, gerrmnatmg rates, contents of protein andstarch were descended in the stored grain which wassenously infested by AGM (Fan et al. , 1989; Chen, 1984)The infestations of AGM to stored grams have beenincreasing as more and more cereal grain has been stored mpeasant household in China since 1980's (LlU, 1987; Wu etal. , 1994 ). Relative abundance of AGM made up 37.28 %of total pest insects discovered m stored grams in some areas( LlU et aI., 1994 ). It is regarded as one of importantmeasures to use the resistance of crop cultivars to AGM in

I Department of Plant Protection, Northwestern AgriculturalUniversrty, Yanglmg, Shaanxi, 712100, Chma

2 Xi'an Arumal & Plant Quarantme Service, Xi'an ,710068, Chma

the integrated AGM management Many works have beendone in the stored paddy (Abraham et al. ,1980; El-Nahal etal ,1979; Russell, 1976). However, the cultivar resistanceof stored wheat to AGM has not been studied yet. In orderto enrich the integrated AGM management, this paper dealsprehmmanly with the relationship of infestation of AGM tocultivars of stored wheat in 1995 -1996

Materials and Methods

Resource of AGM

About 40kg of wheat grams (cultrvar: Xiaoyan 6), dnednaturally in the sun, were nearly equally divided into 4 partsand each part was held in 50cm 35cm 15cm plastics boxrespectively. A great quantity of AGM moths were capturedfrom the barn of stored wheat and put into the plastics boxesWith the nylon net top in order to obtain more insects neededin experiments.

Wheat cultivars

10 wheat cultrvars, including Xiaoyan 6, NWAU 65,Xiaoyan 168, Xiaoyan 107, NWAU 85, Shaan 229, Xiaoyan504, 84 (G) 6, shaan 167 and Jmmai 27, were selected andtested. They were provided by the Institute of Grain Crops,Shanxi Academy of Agricultural Science, the NorthwesternInstitute of Botany, Chmese Academy of Sciences and theInstitute of wheat, Northwestern Agncultural University.All of the wheat cultrvars were Simultaneously and randomlysown into 2m x 1m plots respectively in early October,1995. Cultivating measures were similar to those whichwere used m the general fields from seedlmg to blossomingstage. Two times of 375ml Folimat emulsion per hectarewere sprayed m order to prevent or kill the moths of AGMdepositing eggs on the matunng wheat ears m middle andlate May, 1996 Each cultrvar of wheat was aloneharvested, shelled and dned in the sun when matured. 2000grains from every wheat cultivar were randomly take outand treated With 55°C in constant temperature box for 48h.to kill all of AGM which had infested m the wheat grains infield. Then, they were poured into nylon-net bags andreserved in shady and cool room.

1354

Proceeduup: of the 7 th Internatwnal Working Conference on Stored-product Protection - Volume 2

Preference of depositing eggs of AGM

4 plastic boxes, which AGM reproduced in, were movedmto 4 insectana when the moths of AGM emerged in a greatquantity m middle July The wheat grams of every cultrvar ,which were treated in advance, were divided mto 4 parts as4 repeats and put mto outer diameter 18cm glass cultureboxes free top respectively. The glass culture boxes wereequidistantly arranged around the resource boxes of AGM minsectana. Took off the nylon-net tops on the resourceboxes of AGM and let moths fly out and deposit eggs on thegrains of vanous wheat cultrvarsTurn on hghts (4 of 40W fluorescent lamps) in 7: 00 -

19:00 and turn off lights m other time m msectaria everyday. The glass culture boxes were removed out from theinsectaria after eggs have been depositmg by moths of AGMfor 3 days. 200 wheat grams were randomly taken out fromevery box and the eggs of AGM were exammed gram bygram by Olympus double-tube bio-rmcroscope made m Japan.

Development periods and survival rates of AGM

300 other grams, deposited by AGM precedently, wererandomly taken out from per repeat of wheat cultrvars andreserved naturally m diameter 4cm, height 7cm plasticbottles. The moths of AGM were captured and counted at8: OOam and 20: OOpm every day from the time when they

began to emerge until all out from the wheat grams Thedevelopment penods and survive rates from eggs to mothswere counted.

Infestation loss of AGM

Accordmg to the numbers of AGM emergmg m 300 gramsper repeat of wheat cultrvars, the rates of mfested gramswere estimated and mfested grains and non-mfested gramsweighed with balance TPll - 2 and loss rates of 1000 gramweight counted.

Results and Analyses

Rates of egg-deposited grains and numbers of egg ongrains

Rates of egg-deposited grams and numbers of egg ongrams did not greatly vary as the wheat cultrvars weredifferent (table 1). The vanation coefficient (V. C.) ofthem were only 8.07% and 12.87% respectively in tenwheat cultrvars There were no significant differences ofeither the rates of egg-deposited grains (F = 0.137) or thenumbers of egg on grams (F = 0.267) on the basis ofstatistical pnnciples. It was concluded that the preference ofdepositing eggs of AGM was not ObVIOUSamong the testedwheat cultivars

Table 1.Preference of depositing egg, development penod and survival rate of AGM.

CultrvarPercent of egg Number of eggs Development period (d ) Survival

eposited grain on 100 grams Minimum Maximum Average rate (%)

Xiaoyan 6 4.00 10.75 26 37 30.74 52.29

NWAU65 4.25 11.25 26 38 33.26 51.40

Xiaoyan 168 4.13 13.00 29 37 31.92 56.82

Xiaoyan 107 4.38 12.75 28 37 32.48 52.78

NWAU85 4.13 13.00 27 36 32.08 53.16

Shaan 229 4.75 15.50 25 36 31.54 55.69

Xiaoyan 504 3.88 10.50 26 39 31. 71 57.54

84(G) 6 3.75 12.25 26 42 32.85 48.85

Shaan 167 4.00 13.75 25 38 32.13 52.61

Jinmai Z? 4.75 14.75 28 41 34.56 45.28

X 4.20 12.75 26.6 38.1 32.33 53.34

V.C.(%) 8.07 12.87 5.07 5.31 3.25 7.92

Relativity analysis showed that the interrelationship of therates of egg-deposited grains to the numbers of egg on gramswas significant (R = 0 .7282, t = 3.005) A model, whichcould be used to express the mterrelationslup mmathematics, was built as follows:Y=3.5256X - 2.0648

Here: X-rate of egg-deposited grains (%); Y-number ofegg on grains (eggs/100 grams)

Development periods and survival rates of AGM

Development penods and survival rates, from egg beingdeposited to moth emerging of AGM, were different With

1355

Proceedings of the 7th Internatwnal Workmg Conference on Stored-product Proiectum. - Volume 2

the wheat cultrvars. The minimum of development periodswas 30. 74d. (Xiaoyan 6), the maximum 34.56d. (Jmmai27) and the mean 32. 33d. The maximum of survival ratewas 59.29% (Xiaoyan 6), the muumum 45.28% (Jinmai27) and the mean 53.54%. There seem to be a trend thatthe less the development penod, the more the survival ratein tested wheat cultrvars. It was proved that there wasanalysing the interrelationship, which was statisticallySIgnificant (R = - 0.7560, t = 3.267), of the developmentpenods to the survival rates.

Relativity of preference of AGM to antibiosis ofwheat cultivar

The interrelationship of rates of egg-deposited grains andnumbers of egg on grains, displaying the preference ofAGM, to development penods and survival rates of AGM,showing the antibiosis of wheat cultivars, was analyzed witheach other. Results showed that the significantmterrelationship was not proved between the preference ofAGM and the antibiosis of wheat cultrvars (table 2).Therefore, two mechanism of resistance to AGM could beseparately evolved.

Table 3. Comparison of damages of AGM to wheat cultivars.

Table 2. Relativrty of preference of AGM to antibiosis ofwheat cultrvar ,

factor * interrelation formula R t value

REDG(X) to DP(Y) Y=1.1929X+273143 0.3849 1.180

REDG(X) toSR(Y) Y=69.3320-3.8053X -0.3056 0.908

NEG(X) to DP( Y) Y =0 1997X + 29.2809 0.3119 0.929

NEG(X) toSR(Y) Y=66.8846-1.0633X -0.4129 1.282

* REDG-Rate of egg-deposited grams (%); NEG-Number of egg ongrams (eggs/lOO grams); DP-Development penod (d ). SR-

Survival rate (% )

Comparison of damages of AGM to wheat cultivars

Some differences existed in either the rates of infestedgram or the loss rates of infested grains in vanous wheatcultivars (table 3). The mean of infested gram was 6.77 %and the vanation coefficient 12.43 % m 10 wheat cultivars.The mean of loss rates of infested grams was 37.94 % andthe variation coefficient 8.87 %. It was showed that thedamages of AGM were related to wheat cultrvars to somedegrees.

Cultrvar Rate of infested Weight of 1000 Non-Infested WeIght of 1000 Loss rate of infestedgrain (%) grams (g) infested grams (g) grain (%)

Xiaoyan 6 6.37 44.667 29.266 34.48

NWAU65 5.78 41.833 25.669 38.64

Xiaoyan 168 7.39 45.206 29.221 35.36

Xiaoyan 107 6.73 44.877 26.976 39.89

NWAU85 6.91 40.382 25.671 36.43

Shaan 229 8.63 43.337 29.218 32.58

Xiaoyan 504 6.04 40.235 24.805 38.35

84(G)6 5.98 43.865 26.815 38.87

Shaan 167 7.23 43.622 25.987 40.44

Iinmai Z? 6.68 39.489 21.987 44.32

X 6.77 42.751 25.561 37.94

C.V.(%) 12.43 4.93 8 66 8.87

The interrelation coefficients of rates of infested grains,rates of egg-deposited grains and numbers of egg on grainsto weight of 1000 non-infested grams were 0.2497 (t =0.7294), -0.2168 (t=0.6281) and 0.0440 (t=0.1246)respectively It was further proved that the preference ofAGM to wheat cultrvars was not ObVIOUS.

Discussion

This paper dealed preliminarily With the relationship of

infestation of the Angoumois gram moth to wheat cultrvars.Results showed that there were no significant differences ofthe rates of egg-deposited grains or the numbers of egg ongrains in various wheat cultrvars on the basis of statisticalpnnciple. The development penods or survival rates of AGMmfestmg varIOUS wheat cultrvars were different to somedegrees from egg developing to moth emerging.So were the rates of infested grams or the loss rates of

Infested grains of wheat cultivars else. These differenceswere, however, not proved to be significant m statistics

1356

Proceedings of the 7th Internatumal Worktng Conference on Stored-product Protection - Volume 2

owing to fewer moths or numbers of infested grams insamples. They need to be further studied. Relatrvity of thepreference of AGM to the antibiosis of wheat cultivar wasanalyzed and results showed no significant interrelation.The evolution of both mecharusms could be alone inheredity,

References

Abraham C C., Thomas B , Karunakaran K. et aI. 1972.Relative susceptibility of different vaneties of paddy toinfestation by the Angoumois gram moth, Sitotrogacereallela (Oliv.) (Gelechildae, Lepidoptera ) , asinfluenced by the amylose content of the endosperm.Bulletin Gram Technology, 10, 263 - 266.Chatterji S. M., Dani R. C. & Govmdswami S. 1977.Evaluation of rice vane ties for resistance to Sitotrogacereallela Oliv. ( Lepidoptera: Gelecluidae ). Journal ofEntomological Research, 1,74 -77.Chen Y. X. 1984. Insects in barn (Revised and enlargeded.) Beijing: Agricultural Press, 347 - 350 (in Chinese)Cogburn R. R. 1977. Resistance to the Angoumois grammoth in some vaneties of rough nee from the USDA worldcollection. Journal of Economic Entomology, 70, 753-754.Cogburn R. R. , Bollich, C. N. , Johnston, T. H et aI. 1980.Environmental influences on resistance to Sitotroga

cereallela in Varieties of rough nee. EnvironmentalEntomology, 9(5), 689 - 693.EI-Nahal A. K. M., Ismail I 1, Kamel A. H. et al , 1979.Host ovipositional preference of the Angoumois grainmoth, Sitotroga cereallela Olivo Agricultural ResearchReview, 57(1), 115 -118.Fan J. A., Li N. S., Zhu W. B. et al. 1989. Populationdynamics of the Angoumois gram moth, Sttotrogacereallela (Oliv.), and its influence to the quality ofwheat. Grain Store, 18(3), 10-14 (m Chinese, withEnglish abstract) .Liu S. Y. , Hou Y. M ,LI W. X. et al. 1994. The communitystructure and ItS control strategy of stored wheat insects inpeasant households. Acta Universitatis AgriculturalisBorealsOccidentalis, 22 (Suppl, 2), 1 - 5 (in Chinese,with English abstract).Liu Y. C. 1987. Discussion about how the gram-stored pestsare controlled in facing production. Grain store, 16(1) ,17- 21 (m Chmese, with English abstract).

Russell M. P, 1976. Resistance of commercial rice vane tiesto Sitotroga cereallela Oliv. (Lepidoptera: Gelechiidae ).Journal of Stored Product Research, 12, 105 - 109.Wu J. X., Dong Y. D., Zhang M. H. et al., 1994. Thedistnbution faunas of stored grain pests occurring inpeasant households m Shaanxi. Acta UniversitatisAgriculturahs Boreali-Occidentalis, 22 (Suppl. 2), 25 - 28(in Chinese, With English abstract).

1357