[ Lost in the Landscape ]

under citrus quarantine

The last cou­ple times I’ve gone plant-shopping to one of my favorite nurs­eries I’ve noticed a big line of yel­low police tape stretched in front of the cit­rus plants. A sign nearby states that the plants are under quar­an­tine and can’t be pur­chased. (Good thing I planted my tan­ger­ine last year…)

The quar­an­tine that has impacted the nurs­ery is one that has been imposed on much of the county. Accord­ing to the press release from the Cal­i­for­nia Depart­ment of Food and Agri­cul­ture (omi­nously dated Sep­tem­ber 11) “the quar­an­tine area includes 1,181 square-miles and extends from the inter­na­tional bor­der with Mex­ico up the coast to High­way 78, east to Ramona, and south along local roads and high­ways to the inter­na­tional bor­der at Tecate, Mex­ico.” (The release has a link to a pdf of a map of the bound­eries, but the link was dead as of Sat­ur­day after­noon.) That’s basi­cally all of the city plus a whole pile of ‘burbs.

My gar­den tan­ger­ine is new as of last fall so I’ve been pay­ing a cer­tain amount of atten­tion to it. I also have a grape­fruit, but it’s gen­er­ally self-sustaining and doesn’t require much atten­tion. But after return­ing from the nurs­ery Sat­ur­day I hap­pened to look at the plant and saw some insect dam­age of a sort I’d never noticed before.

That sent me all over the web, look­ing to see if this was the sort of dam­age that would be done by the lit­tle beast that has caused all this com­mo­tion, the Asian cit­rus psyl­lid. There were lots of mugshots of this fairly ugly bug, plus descrip­tions of the plant-wilting dis­ease that it can spread. Nei­ther seemed to be what I had going on in the back yard, however.

It turns out the trou­ble in my lit­tle Tahiti was caused instead by the cit­rus leafminer, an insect first detected in the gen­eral area in 2000. Some bugs can be con­sid­ered basi­cally benign, and this one is one of those. This is from its rap sheet from the Kern County Coop­er­a­tive Exten­sion Ser­vice a cou­ple years ago.

For most, cit­rus leafminer will likely be noth­ing more than a nui­sance, since research from Florida has not linked this pest to any reduc­tions in yield or qual­ity of fruit. How­ever, it is unlikely that there are many farm­ers who get plea­sure see­ing the beau­ti­ful leaves in their orchards become all twisted and knurled. The real prob­lems with cit­rus leafminer are while the trees are in the nurs­ery and dur­ing their first one to three years of devel­op­ment after plant­ing. Dur­ing this time cit­rus leafminer, which loves to feed inside new flush leaves, can cause suf­fi­cient dis­tor­tion and dam­age to caused stunt­ing of the plants.

More of a nui­sance for mature plants, it sounds like. And the dam­age was on only a fairly small por­tion of the plant’s new leaves. That allowed me to appre­ci­ate the fact that the wan­der­ing insect pat­terns inside the leaf have a cool, loopy, geo­met­ri­cal grace to them. I can live with a lit­tle twist­ing and knurl­ing now that I know it doesn’t seem to bother the plant too much…

October 26 2008 | Categories: gardening • my garden | Tags: Asian citrus psyllid • citrus • citrus leafminer • grapefruits • plant quarantines • tangerines | 3 Comments »