A Fundamental Study Based On Colours And Od Orants For Trapping Of Thrips Hawaiiensis

Thrips hawaiiensis(Morgan)is a significant insect pest on banana and mango in tropical industrial crops in China.It seems due to its undeniable hidden habits,so many chemicals are ineffective for control of the thrips.Therefore,there is an urgent need to explore more efficient insect monitoring and integrated pest magagement techniques,afterwards,this would guide field production applications.In view of this,to find suitable trapping technique for T.hawaiiensis,the present study mainly research on behavior preference of the thrips response to colours,lights and ordorants.The contents and results are as follows:1.The activity pattern of T.hawaiiensis population in banana plantation in HainanThe activitiy heights,day activity rhythm,activity changes under different weather situation and population dynamicas of T.hawaiiensis were investigated by using blue sticky cards in the banana plantations.The results showed that T.hawaiiensis were found to be active during heights from 2 to 6 m among 16 measured altitudes of 0.5-15 m.T.hawaiiensis was shown to be active in the hours from 12.00 to 16.00 from noon to ahternoon,while with little activity in the night and morning.In addition,the results revealed that T.hawaiiensis was most active in sunny day,however,little number of the thrips population was observed in cloudy and rainy day,indicating that T.hawaiiensis population activity was clearly associated with weather conditions.The changes in population dynamics of T.hawaiiensis in Chengmai,Lingao and Sanya were also studied and compared.T.hawaiiensis population had a single peak type in the whole year,an increase in population number at the beginning of emergence of banana flowerbud and this reached the peak at the blooming period,while this rapidly decreased when the flowerbuds were cuted,few number of the thrips population was found in other crop periods.These results indicated that the population dynamics of the thrips were closely related to the banana growth period.2 The response of T.hawaiiensis to different colorsIndoor use of positive hexahedron device in the laboratory tests,the results showed that T.hawaiiensis were the most sensitive to blue,especially the blue wavelength was 480 nm,which was the most attractive to the thrips.In the banana field experiments,the effects of different color traps,seven different suspension heights and two different suspension methods on the trapping efficiency of the thrips were studied.The results showed that the blue sticky cards were the most attractive to the thrips.Moreover,those blue sticky cards which parallel to the banana crop rows and with placed 2-3 m above the fround trapped more catches in the banana plantation.3 Behavioral response of T.hawaiiensis to different information odor substancesTo determine the behavioral response of the thrips,30 odorants including volatile compounds and plant essential oils were used in the olfactory test by using a Y-type tube olfactometer.The results showed that the odorants were more attractive to adult thrips than nymphs,especially volatile compounds of neroli,niacin and geraniol,plant essential oils of rosewood essential oil cardamom and verbena displayed higher selective rate than other odorants.On the base of the above results,the further tests used neroli and rosewood essential oil as hobby attractants to determine their ideal concentrations in four low volume fractions(20%,10%,1%,0.1%)by using a 4-arm selective olfactometer.The results showed that a percentage concentration from 1% to10% of the above two compounds were significantly more attactive to the thrips.Furthermore,field experiments were conducted to test the capture efficiency and optimal concentration of selective odorants by using self-handmade trapping device.The results demonstrated that phenylpropionaldehyde,niacin,neryl alcohol and rosewood essential oil were also observed to be more attractive to the thrips than others,and captures were significant higher in the percentage concentration from1% to 10% when benzenepropannal and rosewood essential oil were used as lures.4 Field study on trapping performance of the integrated high-efficiency sticky cardsThe intergrated high-efficiency sticky cards used in the study consisted of blue sticky cards combined with effective ordants as lures.Firstly,nerol was selected as an attractant,and we designed four kinds of binding method to combine the attractant to the blue card.The results indicated that combination method of centrifugal tube(place attractant in it)stick on the blue cards catched more thrips than other treatments.Afterwards,we used above combination method to investigated the effect of different odrants as lures and different concentrations on capture efficiency of the thrips.Similarly,nerol-and rosewood essential oil-blue sticky cards were found more effective to capture the thrips than other lures of odrants.The results also revealed that the the optimal concentration for nerol was ranged from 1%-10%,and 10%-20% for rosewood essential oil,respectively.Finally,on the base of the above findings,we designed the final integrated high-efficiency sticky cards by using nerol and rosewood essential oil,and the optimal concentration of attractants,trap colour,height and placement were all taken into consideration.The results indicated that these integrated high-efficiency sticky cards were shown to effective to catch the thrips,showing that captures were 6.5 times and 5.3 times higher than blue cards with single use,when nerol and rosewood essential oil were used as lures,respectively.